Category: falling balls

The physics and science of falling balls

Why do objects on earth accelerate downward at the same speed regardless of thei…

Lou Bloomfield Leave a comment

Why do objects on earth accelerate downward at the same speed regardless of their mass?

What you mean here is that they accelerate downward at the same rate (“speed” has a particular meaning that isn’t so well suited to discussions of acceleration). This fact comes about because, although massive objects are harder to accelerate, they also experience more weight. Thus a huge stone will fall at the same rate as a small rock because the stone will be pulled downward more strongly by gravity and that extra pull will make up for the stone’s greater inertia.

If you dropped a bullet and at the same time, fired a bullet directly at the gro…

Lou Bloomfield Leave a comment

If you dropped a bullet and at the same time, fired a bullet directly at the ground, wouldn’t the bullet fired at the ground hit the ground first?

Sure it would. The fired bullet will only hit the ground at the same time as the dropped bullet if the fired bullet is shot exactly horizontally. If you fire the bullet at the ground, then it starts out with an enormous downward component to its velocity. The falling bullet doesn’t have this initial downward component to its velocity and never catches up.

Why do two objects of unequal mass fall and hit the ground at the same time?

Lou Bloomfield Leave a comment

Why do two objects of unequal mass fall and hit the ground at the same time?

If one object has twice the mass of the other, then it is twice as hard to accelerate. To make it keep pace with the other ball, it must experience twice the force. Fortunately, gravity pulls on it twice as hard (it has twice the weight of the other ball), so in falling, it does keep pace with the other ball. The two fall together. Just for fun, imagine stepping off the high diving board with two friends. The three of you have essentially identical masses and weights and also fall at the same rate. Now imagine that two of you hold hands as you fall. You are now a single object with twice the mass of your other friend. Nonetheless, you still fall at the same rate. So an object with twice the mass of another falls at the same rate as that other object.

If you fire a bullet horizontally and drop an identical bull at the same moment,…

Lou Bloomfield Leave a comment

If you fire a bullet horizontally and drop an identical bull at the same moment, will they both hit the ground at the same time?

Yes. The fired bullet may travel farther, but it will fall just as quickly as the dropped bullet and they’ll hit the ground at the same moment. This effect explains why you must aim above the target when shooting at something far away. The faster the bullet travels to the target, the less it will drop. An arrow travels slowly enough that it will fall a considerable distance en route. You must aim quite high when shooting an arrow.

Why do you feel no acceleration in free fall, even though you are accelerating?

Lou Bloomfield Leave a comment

Why do you feel no acceleration in free fall, even though you are accelerating?

This wonderful question has many answers. The first, and most direct, is that you do feel the acceleration. You feel an upward fictitious force (not a real force at all, but an effect of inertia) that exactly balances your downward weight. The feeling you experiences is “weightlessness.” That’s why your stomach feels so funny. You’re used to having it pulled downward by gravity but the effect of your fall is to make it feel weightless.