Relative to a free fall acceleration. Medical search. Frequent questions

The relative gravimeter measures the difference of gravity between various locations. (bigislandvideonews.com)
Absolute gravimeters directly measure the acceleration of gravity. (bigislandvideonews.com)
Negative gravity is a confusing term because the problem wasn't one of gravity, or even force, but rather of acceleration and inertia. (damninteresting.com)
Or am I way off?In summary, according to Einstein's equivalence of acceleration and gravity, whoever is accelerating is following spacetime curvature. (physicsforums.com)
I am familiar with Einstein's equivalence of acceleration and gravity. (physicsforums.com)
Given that the acceleration due to gravity near the surface of the earth is 9.8 m/s2, any object in free fall will increase its velocity (in the negative, downward direction, mind you) by 9.8 m/s for every second of flight, regardless of its initial velocity, be it zero, upwards, or downwards, or even any combination of those. (standupeconomist.com)
MB: First off, it seems as if you are referring to forces other than gravity when you say the measured acceleration after one second won't be = g. (standupeconomist.com)
Determining the acceleration due to gravity by using simple pendulum. (markedbyteachers.com)
Also the G apparatus (freely falling mass) can be used to determine the acceleration due to gravity. (markedbyteachers.com)
What is acceleration due to gravity? (markedbyteachers.com)
We have been told that the acceleration due to gravity of earth is 9.81 m/s² or g= 9.81 m/s², however, due to myriad of factors, g in one place differs slightly to other, as u increase the altitude the g decreases. (markedbyteachers.com)
The aim of this investigation is to measure the earth's gravitational field strength, which is also the acceleration due to gravity. (markedbyteachers.com)
Where L is the length of the string or wire to the centre of mass of the bob and g is the acceleration due to gravity. (markedbyteachers.com)
The aim for this experiment is to determine the acceleration due to gravity using a pendulum bob. (markedbyteachers.com)
When an object falls freely under gravity, it experiences uniform acceleration due to gravity. (askanydifference.com)
In summary, frames under identical acceleration, regardless of whether due to gravity or accelerated motion, are locally identical but time runs slower in a gravity well. (physicsforums.com)
It's not clear from the above statement whether you are using 'time runs slower in a gravity well' as an example of how gravity is different from acceleration. (physicsforums.com)
The laws of gravity dictate that a 5 ton SUV, for example, and a 1lb rock, given that their relative densities are so much higher than the resistance presented by the surrounding air, will take approximately the same time to reach the ground when dropped from the same height. (cassiopaea.org)
The time t required for an object to fall from a height h (in a vacuum) is given by the formula t = sqrt(2h/g), where g is the acceleration due to gravity. (cassiopaea.org)
begingroup$ as quickly as practical Practical means no more or less than one gee acceleration (or deceleration) so the crew feel a pseudo gravity like Earth. (stackexchange.com)
The accelerations that are not produced by gravity are termed proper accelerations, and it is only these that are measured in g-force units. (infozone.tv)
Objects allowed to free-fall under the influence of gravity feel no g-force, as demonstrated by the "zero-g" conditions inside a freely-falling elevator falling toward the Earth's center (in vacuum), or (to good approximation) conditions inside a spacecraft in Earth orbit. (infozone.tv)
Since the g-force felt is always a measure of proper acceleration (which, in these cases, is zero, even though the objects are freely changing velocity due to gravity) all of these conditions of free-fall produce no g-force. (infozone.tv)
Zero G in space is because you're in a space capsule accelerating under gravity, orbiting the Earth, or going from one body to another and you're not accelerating [relative to the spacecraft]: the person within the spaceship is accelerating at the same rate as the vessel. (thenakedscientists.com)
Presuming the Earth is in an optimal orbit relative to it's mass and composition, as science and ToR tell us, and relative to gravity, or the gravitational pull of the sun at this distance away. (thenakedscientists.com)
The acceleration of an object is commonly measured in G's (gees), where 1 G represents the acceleration due to gravity on Earth, which is approximately 32.2 feet per second squared (fps²) or 9.8 meters per second squared (m/s²). (selebriti.cloud)
In other words, it is a measure of how much gravity or acceleration is pulling on an object. (selebriti.cloud)
Measuring g force in multiples of gravity removes the mass component and only focuses on the acceleration component. (selebriti.cloud)
Overall, measuring g force in multiples of gravity provides a simple and standardized way to measure and compare the amount of force felt by an object due to acceleration. (selebriti.cloud)
In physics, g force refers to the acceleration experienced by an object in relation to gravity. (selebriti.cloud)
The calculation of g force is based on the concept of acceleration due to gravity. (selebriti.cloud)
When someone throws a ball into the air and watches it to fall, he/she feel confirm that the ball will fall down as it obey the law of gravity. (ukessays.com)
The greater the altitude at release, the greater the time of fall of the weapon, the longer acceleration due to gravity will act on the weapon increasing impact angle and velocity. (uxoinfo.com)
One g is the acceleration due to gravity at the Earth's surface and uses the standard gravity symbol: g n , defined as 9.80665 meters per second squared. (resodynmixers.com)

Force is typically measured in Newtons (N), but impact force may be discussed in terms of a "G-Force", a number expressed as a multiple of g , or earth's gravitational acceleration (9.8 m/s^2). (sparkfun.com)
The standard gravitational acceleration at the Earth's surface produces g-force only indirectly. (infozone.tv)
If the ball hits the ground in 1 s, what is this planet's gravitational acceleration? (nerd-notes.com)
Gravitational acceleration should not be a problem unless tidal forces become significant, unless of course something lies in your path. (scienceforums.net)

Instantaneous acceleration, meanwhile, is the limit of the average acceleration over an infinitesimal interval of time. (wikipedia.org)
All that the limiting process does here is zero in on the instantaneous acceleration. (standupeconomist.com)
But in the case of free fall the acceleration is constant over time so the limit process doesn't nearly have the same impact here as it does for speed since the instantaneous acceleration is always equal to an object's average acceleration. (standupeconomist.com)
The instantaneous acceleration of an object at a specific moment in time is calculated by taking the derivative of its velocity with respect to time. (askanydifference.com)
The formula is:a = dv / dtwhere a is the instantaneous acceleration, v is the velocity, and t is time. (askanydifference.com)

If the speed of the vehicle decreases, this is an acceleration in the opposite direction of the velocity vector (mathematically a negative, if the movement is unidimensional and the velocity is positive), sometimes called deceleration or retardation, and passengers experience the reaction to deceleration as an inertial force pushing them forward. (wikipedia.org)
Both acceleration and deceleration are treated the same, as they are both changes in velocity. (wikipedia.org)
Each of these accelerations (tangential, radial, deceleration) is felt by passengers until their relative (differential) velocity are neutralized in reference to the acceleration due to change in speed. (wikipedia.org)
Closed head injuries typically occur when the head is struck, strikes an object, or is shaken violently, causing rapid brain acceleration and deceleration. (msdmanuals.com)

Pages 176-177: Newton's second law of motion… // That's because we need limits to define acceleration. (standupeconomist.com)
RH: Newton's 2nd law correctly stated says that the NET force on an object equals its mass x its acceleration. (standupeconomist.com)
It is thus experiencing proper acceleration, even without a change in velocity (which is dv/dt, the familiar "coordinate acceleration" of Newton's laws). (infozone.tv)
Calculate the acceleration, forces or mass using newton's 2nd law. (montcalm.edu)
5.06 Apply the relationship (Newton's second law) between the net force on an object, the mass of the object, and the acceleration produced by the net force. (slideshare.net)

An example here is a rocket in free space, in which simple changes in velocity are produced by the engines, and produce g-forces on the rocket and passengers. (infozone.tv)
An accelerometer is a sensor that measures changes in velocity or acceleration of an object relative to free-fall. (gyroplacecl.com)

The standard unit of acceleration is meters per second squared (m/s^2). (askanydifference.com)
For background, the unit of measure of acceleration in the International System of Units (SI) is meters per second squared, or m/s 2 . (resodynmixers.com)

The orientation of an object's acceleration is given by the orientation of the net force acting on that object. (wikipedia.org)
Acceleration is defined as the rate at which an object's velocity changes over time. (askanydifference.com)
Uniform acceleration occurs when an object's velocity changes at a constant rate over time. (askanydifference.com)
Non-uniform acceleration occurs when an object's velocity changes at an irregular rate over time. (askanydifference.com)

Similar to the free-fall absolute gravimeters, HVO's new AQG measures the acceleration of a small test mass in a vacuum. (bigislandvideonews.com)
G force is a physical concept that measures the acceleration of an object due to the gravitational force acting on it. (selebriti.cloud)

What the human body can withstand depends on a combination of the amount of acceleration, its direction and its duration. (scienceforums.net)
This is important because the amount of force felt by an object is dependent on both the amount of acceleration and its mass. (selebriti.cloud)

YB: I think we may just have to agree to disagree, but note (relative to the next paragraphs) that when the book talks about things like velocity and acceleration it's referencing something instantaneous, not something averaged over time. (standupeconomist.com)
Differentiate velocity and acceleration, with mathematical and graphical descriptions. (montcalm.edu)

Such negative accelerations are often achieved by retrorocket burning in spacecraft. (wikipedia.org)
In LISA Pathfinder, precise inter-test-mass tracking, by optical interferometry, allows us to assess the relative acceleration of the two LISA test masses 38 cm apart in a single spacecraft. (elisascience.org)
On LISA, the two sensitive axes in a single spacecraft are close to orthogonal, and as such, the spacecraft can follow both test masses at the same time, resulting in two truly drag-free test masses along their sensitive axis. (lisamission.org)
All the relative attitudes between the test masses and spacecraft can be modulated, allowing measurement of the relevant spring and crosstalk couplings. (lisamission.org)

After what I have read so far (albeit not that much) I do not believe that terminal velocity is possible in the FE theory, as there is nothing to push the ball down, so once it hit friction, it would free-fall after its peak, as if in a vacuum, because no force would be pushing down on it. (theflatearthsociety.org)
If the force of friction is 85.0, what is the net force and acceleration? (nerd-notes.com)

Accelerations are vector quantities (in that they have magnitude and direction). (wikipedia.org)
At any point on a trajectory, the magnitude of the acceleration is given by the rate of change of velocity in both magnitude and direction at that point. (hellenicaworld.com)
5.08 Determine the magnitude and direction of the gravitational force acting on a body with a given mass, at a location with a given free-fall acceleration. (slideshare.net)

The acceleration of the vehicle in its current direction of motion is called a linear (or tangential during circular motions) acceleration, the reaction to which the passengers on board experience as a force pushing them back into their seats. (wikipedia.org)
When changing direction, the effecting acceleration is called radial (or centripetal during circular motions) acceleration, the reaction to which the passengers experience as a centrifugal force. (wikipedia.org)
Metabolically inert infrastructure or buoyant force of fluids secludes self gravitating body from external stronger gravitational field and helps to maintain self gravity's free fall condition. (webmedcentral.com)
When we use units of G-force, we are measuring an objects acceleration relative to free fall towards the earth. (sparkfun.com)
Technically speaking, g is an acceleration, not a force. (sparkfun.com)
G-force refers to the force experienced by an object due to its acceleration relative to free-fall. (askanydifference.com)
The g-force (with g from gravitational) associated with an object is its acceleration relative to free-fall. (infozone.tv)
The 1 g force on an object sitting on the Earth's surface is caused by mechanical force exerted in the upward direction by the ground, keeping the object from going into free-fall. (infozone.tv)
In the absence of gravitational fields, or in directions at right angles to them, proper and coordinate accelerations are the same, and any coordinate acceleration must be produced by a corresponding g-force acceleration. (infozone.tv)
This mechanical force provides the 1.0 g-force upward proper acceleration on the pilot, even though this velocity in the upward direction does not change (this is similar to the situation of a person standing on the ground, where the ground provides this force and this g-force). (infozone.tv)
Technically speaking, g is an acceleration, not a force, but it is useful when talking about collisions because acceleration* is what damages the human body. (foxbotindustries.com)
G force is relative to the acceleration of an object in free fall, and it is commonly used to describe the forces experienced by astronauts, pilots, and racing drivers. (selebriti.cloud)
G force is a measure of the amount of force felt by an object due to acceleration. (selebriti.cloud)
The glue form is removed with little relative force, enough to tear away a small portion of the foam warzone wh free to which it was attached, leaving an unsealed opening to which a vacuum supply line can be attached as an input to the actuator. (storytellercentral.com)
For example, when a dragster accelerates, a force from the track acts on the rear tires to cause the dragster's acceleration.When a defensive guard knocks down a quarterback, a force from the guard acts on the quarterback to cause the quarterback's backward acceleration. (slideshare.net)
A force that accelerates that standard body by exactly 1 m/s2 is defined to have a magnitude of 1 N. The direction of a force is the direction of the acceleration it causes. (slideshare.net)
The release point is specific to a set of release conditions: altitude above ground, airspeed, dive angle, and acceleration ("g" force). (uxoinfo.com)
Force Calculator - calculate force based on mass and acceleration. (sjbcpws.info)

The plot below shows the acceleration measurement expected from LPF placed in context with other missions. (elisascience.org)
The science of LISA Pathfinder consists of measuring, and creating a experimentally-anchored physical model for all the spurious effects - including stray forces and optical measurement limits - that limit our ability to create, and measure, the perfect constellation of free-falling test particles that would be ideal for LISA. (elisascience.org)
The data from this experiment can then be analysed to provide a measurement of the purity of free-fall one can achieve in a more LISA-like configuration. (lisamission.org)
Distinguish observation from measurement and list their relative merits. (montcalm.edu)
This will allow measurement of the LPF acceleration noise in the absence of applied actuation forces along the sensitive x axis, and thus a measurement in the conditions most similar to those of LISA. (lisamission.org)

In this article, we will explore the concepts behind acceleration, the formulae used to calculate acceleration, the benefits of using an acceleration conversion calculator, and some interesting facts about acceleration. (askanydifference.com)
There are several formulae used to calculate acceleration, depending on the information available. (askanydifference.com)
Calculate and describe quantities of linear motion for a fixed or zero acceleration. (montcalm.edu)
Calculate the free-fall rate of speed and distance below the straight line path after a given time. (montcalm.edu)
Acceleration Calculator - calculate the rate of change in velocity. (sjbcpws.info)
Free Fall Calculator - calculate the time for an object to fall. (sjbcpws.info)
Relative Humidity Calculator - calculate the relative humidity. (sjbcpws.info)

In relative terms, so far as life aboard the aircraft is concerned, those things are moving upward rather than downward. (damninteresting.com)

My point is that, though an observer at the center of the sphere experiences zero acceleration, time runs slower for them than for an inertial observer far from any large masses. (physicsforums.com)
If the actuation noise is a limiting factor, then this experiment will result in periods of time where the relative acceleration of the two test masses is lower than before, and therefore closer to pure geodesic motion. (lisamission.org)

Free-fall absolute gravimeters, the most common type, use lasers to measure the free-fall acceleration of a small reflecting prism (a test mass) in a vacuum. (bigislandvideonews.com)
Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. (jove.com)
Because when the falling guy was in free-fall, he was not effected by gravitational time/length/mass warps (according to spaghetti monster's frame of reference). (physicsforums.com)
Kinematic quantities of a classical particle: mass m, position r, velocity v, acceleration a. (hellenicaworld.com)
After a few minutes of free drift, the actuation is restored for a short time to 'kick' the test mass back to its nominal position. (lisamission.org)
A distorted starfield seen by a fast-moving astronaut will show an apparent concentration of stars in the forward direction - if the gravitational attraction of each of these stars appears to point to its visible position, the astronaut should expect to undergo a free-fall acceleration forwards, towards the region of highest mass-density. (relativitybook.com)
Understanding the forces which disturb the test mass free-fall is the commissioning of the LISA drag-free and gravitational reference systems, mitigating risk and ensuring the best possible sensitivity. (lisamission.org)

The measured LISA Pathfinder differential acceleration noise level will represent a benchmark upper limit for the LISA acceleration noise budget. (lisamission.org)
We will push beyond this verification, however, working towards the goal of a full physical model of all relevant acceleration noise sources, allowing accurate predictions for the lower frequencies and higher performance that is desired for LISA. (lisamission.org)

Proper acceleration, the acceleration of a body relative to a free-fall condition, is measured by an instrument called an accelerometer. (wikipedia.org)
A gyroscope is a device used to measure rotational motion while an accelerometer measures linear acceleration. (gyroplacecl.com)

This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. (infozone.tv)
Because of these strains (weight forces), large proper accelerations (large g-forces), may be destructive. (infozone.tv)
5.05 Sketch a free-body diagram for an object, showing the object as a particle and drawing the forces acting on it as vectors with their tails anchored on the particle. (slideshare.net)
Newtonian mechanics relates accelerations and forces. (slideshare.net)

In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. (wikipedia.org)
that is, the area under the curve of an acceleration vs. time (a vs. t) graph corresponds to the change of velocity. (wikipedia.org)
Likewise, the integral of the jerk function j(t), the derivative of the acceleration function, can be used to find the change of acceleration at a certain time: Δ a = ∫ j d t . {\displaystyle \mathbf {\Delta a} =\int \mathbf {j} \,dt. (wikipedia.org)
Acceleration has the dimensions of velocity (L/T) divided by time, i.e. (wikipedia.org)
Unlike relative gravimeters, absolute gravimeters do not drift nor degrade in accuracy over time. (bigislandvideonews.com)
The average acceleration of an object over a period of time is calculated by dividing the change in velocity by the change in time. (askanydifference.com)
The formula is:a = Δv / Δtwhere a is the average acceleration, Δv is the change in velocity, and Δt is the change in time. (askanydifference.com)
The formula for uniform acceleration is:v = u + atwhere v is the final velocity, u is the initial velocity, a is the acceleration, and t is time. (askanydifference.com)
The formula for non-uniform acceleration is:v = u + ∫a dtwhere v is the final velocity, u is the initial velocity, a is the acceleration, and ∫a dt represents the integral of acceleration with respect to time. (askanydifference.com)
Time dilation is not directly related to acceleration, so I don't understand your point here. (physicsforums.com)
Both experience zero acceleration but not the same time rate. (physicsforums.com)
An object in `free fall´ i.e. falling through thin air, will take a specific amount of time to reach the ground. (cassiopaea.org)
In Earth-based gravitational wave measurements, the test particles are the pendulum-suspended mirrors of a Michelson interferometer, which are effectively free-falling, on time scales much shorter than the pendulum period, along the line of sight connecting them. (elisascience.org)
But they're just free-falling around the Earth all the time so that they're weightless, but that's not the same as zero G? (thenakedscientists.com)
While freefall might entice most people to try skydiving, a surprising amount of first time jumpers enjoy the parachute ride even more than the freefall. (albertaskydivecentral.com)
Some air to surface ordnance have features to restrict their free fall speed to allow the deploying aircraft enough time to get out of the effectiveness or danger area of the weapon being deployed. (uxoinfo.com)
it detects acceleration in selected planes and converts the data into "counts," which are then measured in specific time intervals or epochs. (cdc.gov)

This EJS simulation allows the user to simulate free fall relative to two inertial frames. (compadre.org)

If the vehicle turns, an acceleration occurs toward the new direction and changes its motion vector. (wikipedia.org)

I actually disagree with this but I think it IS fair to say that "acceleration is easier to understand WITH calculus. (standupeconomist.com)

The EJS Falling Body On Rotating Earth 2D model illustrates the trajectory of an object dropped from rest (relative to the rotating Earth) from a point above Earth's equator. (compadre.org)

To help distinguish acceleration relative to free-fall - the focus here - from simple acceleration (rate of change of velocity), the unit g (or g ) is often used. (resodynmixers.com)

Determine the relative amount of inertia between objects by experiment. (montcalm.edu)
Est imate the relative motion of objects. (montcalm.edu)

Yes, acceleration is defined as a derivative, i. e., a limit, but if it is constant over a second, you will indeed see delta v = 9.8 m/s. (standupeconomist.com)

Much of the experimentation in gravitational physics requires measuring the relative acceleration between free-falling, geodesic reference test particles. (elisascience.org)
have seen that part of physics is a study of motion, including accelerations, which are changes in velocities. (slideshare.net)
Poderoso and free physics calculators for everyone. (sjbcpws.info)

Once A net =0 the relative velocity will be constant which is the same as terminal velocity. (theflatearthsociety.org)

Acceleration is one of several components of kinematics, the study of motion. (wikipedia.org)
Just to be sure I'm clear, all motion is relative. (physicsforums.com)
The result would be a deeply unstable universe in which any form of relative motion would be liable to cause a runaway positive-feedback acceleration. (relativitybook.com)

How to define a level of danger of acceleration? (scienceforums.net)
How to define a level of danger of acceleration in gravitational field and without gravitational field? (scienceforums.net)

First measurements in the 1800s and 1900s were difficult and often unsuccessful until portable relative gravimeters were developed. (bigislandvideonews.com)
Since the 1970s, relative gravimeters have been successfully used for measurements at over 65 benchmarks on the Island of Hawai'i. (bigislandvideonews.com)
It is useful for scientists, engineers, and students who need to work with acceleration measurements in different units. (askanydifference.com)

If you feel that you have taken a serious fall, please visit a qualified and licensed professional for proper treatment. (sparkfun.com)
These are examples of coordinate acceleration (a change in velocity) without proper acceleration. (infozone.tv)

The pilots would have to be in excellent physical shape, and mentally prepared to tolerate two second periods of heavy acceleration during each 30-second leap. (stemgeeks.net)

A static gravitational field does not affect the energy of anything in free-fall, so any fixed observer would see a falling object or light beam to have constant energy or frequency. (physicsforums.com)
Cart 1 has constant acceleration, and Cart 2 has constant velocity. (compadre.org)
When the student is still 40.0 m from the bus, it starts to pull away, moving with a constant acceleration of 0.170 m/s. (nerd-notes.com)
The simple algorithm used above reflects the constant acceleration during free fall accurately, supposed we're neglecting the effect of air drag. (numlock.ch)

Qualitatively relate torque and moment of inertia to relative angular acceleration. (montcalm.edu)

Everyone is motionless in their own frame of reference but for you to stay motionless relative to the Earth, the Earth has to push up against you while spacetime curvature wants you to move toward the center of the Earth. (physicsforums.com)
The guy in free-fall is happily following spacetime curvature. (physicsforums.com)

What we know about the dangers of acceleration is purely from experiment (and accident). (scienceforums.net)

When an aircraft accelerates downward faster than it would in free fall, anything not bolted down, like the blood surging through the pilot's vessels, will accelerate more slowly due to its own inertia. (damninteresting.com)

For example, for the f(t) equation the number 2 represents the initial position (in meters), the +19.6 is the initial speed (in m/s) and the - 4.9 is half the acceleration (in m/s2). (standupeconomist.com)

acceleration of the earth. (theflatearthsociety.org)
The air beneath you is being accelerated by the earth, which is slowing your relative acceleration until relative velocity is zero. (theflatearthsociety.org)
How high would I have to hit a baseball that it would no longer fall back to earth? (thenakedscientists.com)
The couches are designed to provide full body support during repeated accelerations of almost three Earth gravities. (stemgeeks.net)

However, it is useful when talking about collisions because acceleration ( the change in speed and/or direction ) is what damages the human body. (sparkfun.com)

Here in this video, Density is discussed and then relative density is explained along with the formula. (educationlessons.co.in)
We generally use the term relative density to relate the density if one object with the other standard liquid (i.e water). (educationlessons.co.in)
So its definition is given as below: Relative Density: It is defined as a ratio of density of the object to the density of water. (educationlessons.co.in)

RH: Page 177: Again, you don't NEED limits (as stated at the top of P5) to understand acceleration but they certainly can help. (standupeconomist.com)
The information can becomes important when characterizing ranges because the location of potential UXO falls within the specifications and limits of the ordnance deployment process. (uxoinfo.com)

Acceleration is the rate of change of velocity. (hellenicaworld.com)
Dangerous is jerk-rate of change of acceleration. (scienceforums.net)
It's important to note that at this rate of acceleration, you'd reach the speed of sound (767 mph) in just under 35 seconds - an insane thought. (selebriti.cloud)

An object on the Earth's surface is accelerating relative to the free-fall condition, which is the path an object would follow falling freely toward the Earth's center. (infozone.tv)

And don't forget, we already do the highest skydives in Canada at industry standard rates so you'll already be doing more than 50% more freefall than anywhere else in Alberta! (albertaskydivecentral.com)
Their magnitudes are defined in terms of the acceleration they would give the standard kilo- gram. (slideshare.net)

does that apply to people in a free fall toward a gravitational body or only to people that are on the ground (or a platform or what have you) and who are feeling the 'acceleration' of the ground toward their feet? (physicsforums.com)
Construct free body diagrams to demonstrate an understanding of various physical situations. (macomb.edu)

Acceleration due to air resistance. (theflatearthsociety.org)
The only explanation is that the floors below the impact point offered no resistance whatsoever allowing the building to fall in `free fall´ with only air as resistance. (cassiopaea.org)

Of course, feel free to modify and adapt the system to suit your various citizen science needs. (sparkfun.com)

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