A20kg tennis ball launcher shoots a 0.057kg tennis ball across a frictionless court. if the tennis ball's velocity after it is launched is 36m/s to the north , what is the velocity of the tennis ball launcher

0.103 m/s to the south

Explanation:

The total momentum of the launcher+ball system must be conserved before and after the launch, so we can write:

where

is the total initial momentum (before the launch)

is the mass of the launcher

is the velocity of the launcher after the launch

is the mass of the ball

is the velocity of the ball after the launch (we take the north direction as positive)

Solving for , we find

and the negative sign means that the direction is south.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide