why is acceleration of an falling object constant?
2006-12-05 15:57:24 · 6 answers · asked by Stephanie 1 in Science & Mathematics ➔ Physics
It is constant because the gravitational pull on all free falling objects is constant at 9.81m/s^2
2006-12-05 16:04:36 · answer #1 · answered by Blue 4 · 0⤊ 0⤋
Forgive me if I'm wrong, but I think you might be asking why all objects, regardless of their weight, fall with the same rate of acceleration. The common misconception is that gravity pulls on all objects with equal force. It does not. Place a heavy object on one side of a double pan balance and a light one on the other and see if you still think gravity pulls on both with equal force. Why, then, doesn't the heavy one fall faster when dropped? Its simply a matter of mass and Newton's second law. The heavier object would accelerate faster when dropped if the force of gravity were the only factor involved. However, if it is heavier it also has more mass and therefore according to Newton should accelerate more slowly. (A = F/M) In the case of free fall without air resistance F (due to gravity) and M will always be directly proportional and cancel each other out. If this doesn't fully explain it, plug some values into the formula. Lets say an object has a mass of two kg. A = 2kg/2kg. Now double the mass of the object to 4 kg. Now A = 4kg/4kg. Triple it A = 6kg/6kg. See ? The rate of acceleration in this example is always one. In practicality multiply the one by the constant of gravity for whatever planet you're working on. Regardless of what we do to the mass of the object, the acceleration when it falls remains the same.
2006-12-06 04:44:42 · answer #2 · answered by JimWV 3 · 0⤊ 0⤋
Because the acceleration is provided by gravity and is
F = MmG/r² where M is the mass of Earth, m is the mass of the 'thing' being dropped, r is the distance between the centers of mass, and G is the gravitational constant (6.672*10^-11).
In point of actual fact, this acceleration is *not* constant (since r becomes smaller as the object falls) but, compared to the radius of the Earth (which is about 6378 km) it's usually too small to worry about.
Doug
2006-12-06 00:09:34 · answer #3 · answered by doug_donaghue 7 · 0⤊ 0⤋
you must realize the forces acting against the object. if you neglect air and other factors and only include gravity. So if the amount of mass between the object you throw and the center of gravity stays the same, you can assume gravity will be constant. If the mass did change, ie. you dropped it down a well to the center of the earth, things may turn out a little different. Gravity is depends on mass pulling on the object.
2006-12-06 00:21:56 · answer #4 · answered by moreplantsforme 2 · 0⤊ 0⤋
because gravity is constant. acceleration is not speed. if something is traveling upward at 9.81 m/s (opposite of acceleration of gravity) then after one second, it would be traveling in neither direction, and after two seconds downward at -9.81 m/s, and continue until it reached maximum velocity. one thing that might effect this is air resistance.
2006-12-06 00:01:42 · answer #5 · answered by arj7002 2 · 0⤊ 0⤋
because gravitational acceleration is constant.
2006-12-06 00:01:43 · answer #6 · answered by pigley 4 · 0⤊ 0⤋