Question

Li and Raj are playing football. They take turns trying to run past each other with the football. Li weighs 125 pound and Raj weighs 175 pounds. Li discovers that if he changes direction quickly when running, he can always dodge out of the way before Raj can tackle him.

Why is Li able to avoid Raj’s tackle? Choose the best description.

Raj has more mass and therefore more inertia, so he can change his motion more easily than Li.
Raj has more mass and therefore less inertia, so he can change his motion more easily than Li.
Li has less mass and therefore more inertia, so he can change his motion more easily than Raj.
Li has less mass and therefore less inertia, so he can change his motion more easily than Raj.

Answer 1

Li has less mass and therefore less inertia, so he can change his motion more easily than Raj.

(Inertia is a measure of how hard it is to change an object's motion — more mass means more inertia, so Raj, being heavier, is slower to change direction.)