Question

A 0.15-kilogram baseball moving at 20 meters per second is stopped by a catcher in 0.010 second. What is the average force stopping the ball?

Answer 1

The force is `=300N`

Explanation:

The impulse is equal to the change of momentum

`F*t=mDeltav`

The mass is `m=0.15kg`

The change in velocity is `Deltav=20-0=20ms^-1`

The time is `t=0.010s`

So,

`F=(mDeltav)/t`

`=(0.15*20)/0.01=300N`

Answer 2

I got `300N`

Explanation:

I would use the Theorem of Impulse and change in Momentum:

`F_"av"t=Deltap=p_f-p_i`

`F_"av"*0.01=0-(0.15*20)`

`F_"av"=-(0.15*20)/0.01=-300N`

opposite to the direction of motion (assumed positive)