 #1
Edel Crine
 89
 12
 Homework Statement:

Two identical 0.50kg carts, each 0.10 m long, are at rest on a lowfriction track and are connected by a spring that is initially at its relaxed length of 0.50 m and is of negligible inertia. You give the cart on the left a push to the right (that is, toward the other cart), exerting a constant 5.0N force. You stop pushing at the instant when the cart has moved 0.40 m. At this instant, the relative velocity of the two carts is zero and the spring is compressed to a length of 0.30 m. A locking mechanism keeps the spring compressed, and the two carts continue moving to the right.
(a) What is the work done by you on the twocart system?
(b) How far does the system’s center of mass move while you are pushing the left cart?
(c) By what amount do you change the system’s kinetic energy?
 Relevant Equations:
 w=f*d
<work done a system>
a) w=5N*(0.4m)=2J
I think this is right, but
b) center of mass initial = ((0.5kg)(0.05m)+0.5kg(0.65m))/1kg = 0.35m
center of mass final = ((0.5kg)(0.45m)+0.5kg(0.4+0.1+0.3+0.25))/1kg = 0.75m
I'm not sure for this one... How can I calculate the displacement of the center of mass??
a) w=5N*(0.4m)=2J
I think this is right, but
b) center of mass initial = ((0.5kg)(0.05m)+0.5kg(0.65m))/1kg = 0.35m
center of mass final = ((0.5kg)(0.45m)+0.5kg(0.4+0.1+0.3+0.25))/1kg = 0.75m
I'm not sure for this one... How can I calculate the displacement of the center of mass??