In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it.
An object in the technical sense of the term "free fall" may not necessarily be falling down in the usual sense of the term. An object moving upwards might not normally be considered to be falling, but if it is subject to only the force of gravity, it is said to be in free fall. The Moon is thus in free fall around the Earth, though its orbital speed keeps it in very far orbit from the Earth's surface.
In a roughly uniform gravitational field, in the absence of any other forces, gravitation acts on each part of the body roughly equally. When there is no normal force exerted between a body (e.g. an astronaut in orbit) and its surrounding objects, it will result in the sensation of weightlessness, a condition that also occurs when the gravitational field is weak (such as when far away from any source of gravity).
The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an atmosphere without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamic drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching terminal velocity produces the sensation of the body's weight being supported on a cushion of air.
From a thread in engineering:
My point is this: though the Earth accelerates the feather and the ball bearing equally, the feather and the ball bearing do not accelerate the earth equally. As a result, the time to impact for the ball bearing will be less than for the feather. For objects that...
hi. I've been trying to do this problem for about 5 hrs...and i still can't get it! :bugeye: If anyone of you could please point me in the right direction, i'd really appreciate it.
The Problem is: A rock dropped from a cliff falls one-third of its total distance to the ground in the last...
If a body is in freefall and has reached its terminal velocity say 56 metres/s, its acceleration is zero, how do you work out with what force it would hit the ground
hi there, first post, hopefully not many more to come, i can usually do these problems but I am swamped, but then so is everyone else, just can't think about this stuff...
You are in an elevator at the top of the CN tower. You have a pendulum and allow it to oscillate. The elevator falls to...
I’m trying to measure g using freefall. I’ve conducted the experiment and now I’m struggling with the formula. The formula we’ve been told to use is:
S = ut ½ at2
Substituting a for g (because that’s what I’m trying to find).
S = ut ½ gt2
The initial Speed is 0 therefore I can remove...
We all know that with Newtonian physics that it doesn't matter in freefall, what the mass of an object is, the only thing that matters is the height from which it dropped (given no external force and all)
But why is that true? Why doesn't it depend upon mass?
i have read in a book or seen...
Ok I am at this problem for hours and I am still nowhere, I am just wondering if any of you can help.
Here is the question
A rock is dropped from rest into a well. If the sound of the splash is heard 2.42s later, how far below the top of the well is the surface of the water? (take the...
A rock is shot vertically up froma building and starts falling back to Earth after 1.60 seconds. After 6.00 seconds, it hits the ground. Constant acelleration of 9.81 m / s^2.
a. What is initial velocity?
b. What is max height above building?
c. How tall is the building?
I got the...
I have an answer that does not seem right:
The raindrop falls from 1700m high with constant acceleration of 9.81 m / s^2
What is the velocity of the raindrop not considering any resistance?
i used y - yo = vo * t - (1/2) g t^2 to get the time to hit the ground at 18.62 seconds.
I then...
I'm having some problems with this question, A ball is thrown directly downward, with an initial speed of 8.25 m/s, from a height of 29.4 m. After what time interval does the ball strike the ground?
I tried 29.4 + 8.25 m/s(x) + 1/2(-9.8m/s)(x), but that didn't turn out to be right. Can I get...
A drowsy cat spots a flowerpot that sails first up and then down past an open window. The pot was in view for a total of 0.61 seconds, and the top-to-bottom height of the window is 2.45 meters. How high above the window top did the flowerpot go?
I first tried to calculate the initial velocity...
Well, I'm not even sure if freefall is the right word, but my first quandary is as followed:
If two objects fall from the same height, and one object will begin to rotate after it has been release (ie. a yoyo), while the other will not rotate, then the rotating object will accelerate slower...
How long does it take typical inelastic rope to stop a person in freefall?
I'm taking a gun-safety course and the instructor claims that for a 200lb person falling 1 meter out of a tree stand before their safety harness halts their fall, it applies a force of 1700 pounds to the body. I feel...
Here is a problem from my book:
If a car rolls gently (initial velocity = 0) off a vertical cliff, how long does it take to reach 90km/h?
It seems easy, and I have been breezing through all teh other ones like it's my job, but for some reason this one gets me. I knwo it's possible, but I...
In QM, particles are treated as either waves or particles, a duality exists. A test particle in freefall is used in all manner of ways to explain certain phenonema.
Can the same experiments be equivilent to waves?..can a wave be explained in any way as in 'freefall'?
It is say when an astronaut is in a spaceshuttle orbiting the Earth, he feels "weightless".
My physics teacher says that is not true, he said that it is mere the sensation of the astronaut not physical reality.
But from my knowledge, the weighless felt by the astronaut is because of he is...
Just a little question.
I'm a little curious. In the classical sense, a reference frame in freefall would, of course, be said to accelerate. However, no forces are felt within a freefalling reference frame. Am I correct, then, in assuming a freefalling reference frame to be an inertial...