Question

1. A wagon containing two boxes of gold and having a mass of 400 Kg altogether has been cut loose from the horses by an outlaw when the wagon is up on slope as in the sketch. Assume that the wagon rolls down the road with negligible friction. The outlaw plans to have the wagon rolls back down the slope and across the level ground and then crash into a canyon where his confederates wait. But in a tree L = 30 m from the cliff wait Batman of mass 80 Kg and Robin of mass 70 Kg (they both made A in Phys 1401). They drop together vertically into the wagon as it passes beneath them

(a) If the wagon has a speed of 20 m/s just before

   Batman and Robin jump into it, what is the magnitude and direction of the momentum of the wagon?

(b) Calculate the speed of the wagon just after

   Batman and Robin jump into it.

(c)  If it takes Batman and Robin 1.5 seconds to grab the gold and jump out, will they make it before the wagon goes over the cliff? Prove your answer numerically.

(d) (10 pts) Let us now assume that Batman and Robin have no cliff to worry about. They decided to throw out a big chunk of gold so that the wagon will reverse its direction.

To which direction they should throw the gold?

Answer 1