Why Does A Bowling Ball Move Without Acceleration?

When you throw a bowling ball down the alley, it starts moving immediately.

Even though you don’t apply any force to it for a little while, it still moves down the alley.

Why does this happen?

It’s all thanks to gravity.

In this blog post, we’ll talk about why gravity makes the bowling ball move and how acceleration affects its motion.

We’ll also look at some real-world examples to help make everything clear.

So read on to learn more about why the ball moves without acceleration.

Related: How heavy are bowling balls?

What makes a bowling ball move without acceleration?

Gravity makes the ball move without acceleration. (source)

When you drop it onto the ground it starts moving down immediately, but there’s no force on it during that brief moment before it starts to move.

The same thing happens when you throw it down the alley.

There is no force on it as it leaves your hand, but there is a force that acts on it once it’s in the air.

In this case, that force is gravity.

In fact, gravity is an acceleration.

This means that once you take away all of the other forces acting on the bowling ball (friction and air resistance) there is a constant downward acceleration that the ball experiences throughout the entire flight.

This means that right when you release it, it starts moving at an upward velocity of 9.8 m/s/s (or 32 ft/s/s).

The negative sign tells us it’s going downward, and the magnitude is equal to its starting upward velocity.

But it only continues to accelerate downward as it falls toward the ground, eventually reaching a velocity of -6.5 m/s/s (or 19 ft/s/s).

Put it simply, gravity acts on the ball the whole time, there just isn’t any actual force that acts on it during that brief moment when you release it.

Once gravity starts acting, though, the ball is continually accelerated toward the ground until it hits it. (source)

That’s why the ball moves without acceleration.

What is acceleration and what does it mean for the ball?

Acceleration is a change in velocity over time.

It’s sometimes referred to as a change in speed, but it’s actually the opposite of speed.

If an object has constant velocity (the same speed and direction), then it doesn’t experience acceleration.

But if the velocity changes at all, even only slightly, then it experiences acceleration.

This means that if the bowling ball is thrown down the alley, it experiences acceleration.

First, there’s a constant downward acceleration due to gravity.

Eventually, though, the velocity changes very slightly as it starts to move forward into the air.

This slight change in velocity results in an ever-so-slight change in acceleration experienced by the ball, from gravity to air resistance.

You can tell it’s a change because the acceleration only changes by a very small amount as the ball starts moving forward instead of downward.

In fact, this is possible thanks to inertia.

If the bowling ball didn’t have inertia, then there wouldn’t be any way for it to continue moving instead of staying at rest due to the constant downward acceleration of gravity.

What is inertia and what does it have to do with the ball’s motion?

Inertia is the resistance of an object to any change in its state of motion. (source)

Or, put more simply, it’s how hard it is for something to start or stop moving.

The greater the mass of an object, the more it resists changes in motion.

The bowling ball has a much greater mass than the air molecules that surround it and so their constant collisions with it don’t affect it very much.

This is why we can throw the ball down the alley instead of just dropping it.

When we drop something, there’s still a downward force on it due to gravity, which means that there’s a change in its velocity.

If you drop one bowling ball and another with the same mass but twice as much inertia (like a beach ball), then they’ll both hit the ground at the same time.

What factors affect the acceleration of the ball?

why does a bowling ball move without acceleration

The ball’s acceleration is affected by several different factors.

Gravity is the main factor, but air resistance also plays a role.

When you drop something it accelerates downward due to gravity alone until it hits the ground.

As soon as it begins falling, however, there’s an opposing force acting on it: air resistance.

This causes what we call terminal velocity, which is the point where the downward acceleration of gravity and the upward acceleration of air resistance balance each other out and result in a constant velocity.

With an object like a bowling ball, there’s also another opposing force: rolling friction.

This is just like regular friction except that it acts opposite to motion rather than motion itself.

Rolling friction acts to slow it down as it experiences a constant downward acceleration due to gravity.

As far as other factors go, there’s not much else going on.

The mass of the bowling ball isn’t changing and its motion doesn’t change from one moment to the next.

So those things don’t affect it at all.

This is why bowling balls have practically constant acceleration as opposed to changing from one moment to the next.

Does air resistance have an impact on the acceleration of the ball?

Yes, definitely.

This is why we can’t just say that the acceleration of a bowling ball is constant due to gravity alone.

The downward force of gravity is constantly changing as it starts and stops accelerating, and the upward force of air resistance also changes accordingly.

The magnitude of these forces might not change, but their direction changes.

An object moving downward experiences a downward force, but an object accelerating downward does not.

So air resistance has an effect on the acceleration of the ball, even though its magnitude doesn’t change.


Inertia is what allows the ball to keep moving once it’s been set in motion.

It’s the resistance of an object to any change in its state of motion, and the greater the mass of an object, the more inertia it has.

This is why we can throw a bowling ball down an alley- because it has more inertia than air molecules surrounding it, they don’t have enough force to stop it from moving.

Other factors that affect acceleration are gravity and rolling friction.

Gravity is constantly pulling an object downward, but air resistance (and rolling friction) work to oppose this movement and eventually cause terminal velocity.

Last updated on March 2, 2023