Here's why:

* Inertia is the tendency of an object to resist changes in its motion. The more massive an object is, the more inertia it has.

* A bowling ball is significantly more massive than a ping pong ball. This means it has much more inertia.

* To stop an object, you need to overcome its inertia. The bowling ball's greater inertia means you need to apply more force to stop it, even if it's moving at the same speed as the ping pong ball.

In simpler terms, the bowling ball is "lazier" and wants to keep moving because it's heavier.