Please Help A 6.0 kg cart moves at a velocity of 12 m/s. The cart bounces off a wall causing it to rebound in the opposite direction at a speed of 18 m/s.

What is the change in the earth's momentum? At for collision is 0.45 earths is the average force from the wall on the cart?
Delta t for collisions is 0.4s

answer; /// i believe that the correct answer is (c)

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min