Question

A car that weighs 7,000 N is accelerated from rest to a velocity of 25 m/s eastward by a force of 1,000 N. (a) What was the change in momentum of the car? (b) How long did the torce a to change the momentum of the car?

Answer 1

Given:

$mg=7000\:\rm N$

$F=1000\:\rm N$

$\Delta v=25\:\rm m/s$

(a)

$$\Delta p=m\Delta v\\ =7000/9.8*25=17500\:\rm kg\cdot m/s$$

(b)

$$F=\frac{\Delta v}{\Delta t}$$

$$\Delta t=\frac{\Delta v}{F}=\frac{17500}{1000}=17.5\:\rm s$$