Question

Please help me answer this question about force and gravity.? Thank you!

Answer 1

No, Alec is incorrect

Explanation:

For objects on the surface (or close to the surface) of the earth, gravitational acceleration will always remain the same, regardless of shape.

Think about some of the kinematic equations we'd use to model a falling object under the influence of gravity:

`Delta(y) = v_(0y)t - 1/2"g"t^2`
`2(-g)Deltay = v_f^2 - v_0^2`

Do you see a mass in any of these equations? No! These equations are independent of mass, because gravitational acceleration is solely dependent on the mass of the earth. The reasons for this are not too difficult to understand (I daresay you'll study them very soon), but in the interests of not straying too much, I will just link you to this video by Khan Academy that explains it, which you can watch if interested.

Why does the crumpled paper fall faster though? Well, that's because there is also air resistance acting on these two objects. A flatter piece of paper invites more air to push against it, while the crumpled sheet is does not.

All this says, however, is that they fall at different speeds due to the different magnitudes of air resistance acting on them. Not due to "lesser" gravitational acceleration.

If you were to repeat this experiment in vacuum, you'd discover that both fall at the same time. In fact, you could drop an elephant and a feather and they'd hit the ground at the same time! That's pretty cool, and goes to prove our point that acceleration due to gravity does not depend on the masses of the objects in question, and certainly not on whether or not they're crumpled.

Hope that helped :)

Answer 2

Alec probably needs to go and review his Physics textbook...

Explanation:

...The force of gravity on earth, no matter the object is approximately 9.8 m/`s^2`. The reason the crumpled paper hits the ground first is because of air resistance. A crumpled piece of paper has less surface area than an piece of paper that is not crumpled. More surface area means more air resistance.

Think of the crumpled piece of paper as you falling from an airplane without a parachute. You accelerate downward. Now lets say the paper that is not crumpled is a parachute without the parachutist. As it falls (the force pulling it down is equal to the force pulling the you down), the force of air pushes against the parachute. The resulting net force is a negative acceleration downward.