Question

A circus bear sits at the back of a 3m-long cart rolling horizontally with a speed of 2 m/s heading in
the positive x direction. The bear has mass 100 kg, the cart has mass 40 kg. At time t = 0, the front of
the cart is at x = 0.
(a) Find the position of the center of mass of the system at t = 0.

Now, the bear rolls slowly to the other end of the cart, moving at a speed
of 1.5 m/s relative to the cart. He stops when he reaches the other end.

(b) What is the speed of the cart with respect to the ground while the
bear walks? (Hint: does the speed of the center of mass change?
Remember that the question gives you the relative velocity of the bear
to the cart, not of the bear to the ground.)
(c) At t = 2 seconds, at what horizontal position is the center of mass
of the cart?
(d) At t = 2 seconds, at what horizontal position is the bear?

Answer 1