Question

A baseball of mass m, initially at rest, is struck by a bat so that it acquires a speed v. If t represents the duration of the collision between the bat and the ball, which one of the following expressions determines the magnitude of the average force exerted on the ball?
A) (1/2)mv2
B) mv/t
C) (1/2)mv2t
D) mt2/(2v)
E) mvt

Answer 1

Answer:

B)mv/t

Explanation:

The gain in momentum of the ball is generated by the impulse by the force from the bat over the collision duration t

$\Delta p = m\Delta v = F t$

where m is the mass of the ball, Δv = v is the gain speed (since the ball was at rest initially), F is the magnitude of the force from the bat, and t is the collision duration. We can solve for F in term of m, v and t

$F = \frac{mv}{t}$

So B) is the correct answer