Question

1200kg car is traveling at a velocity of 20m/s the car then does 3000W of power for 20 seconds what is the change in momentum?

Answer 1

Work done by car

$W=3000\times20=60000J$

Work done will be equal to change my n kinetic energy

$\frac{1}{2}(1200) (v^2-20^2) =60000\\v=22.36m/s$

Change in momentum

$\Delta P=1200(22.36-20) =2832kgm/s^2$