A wooden block rests on a frictionless horizontal cart that moves east at a constant…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power
Problem
A 2.0kg wooden block rests on a frictionless horizontal cart that moves east at a constant speed of 3.0m/s relative to the ground. At time t=0, a horizontal spring fixed to the cart launches the block so that, immediately after losing contact with the spring, the block moves east at 5.0m/s relative to the ground.
Answer the following.
(a) Compute the block’s translational kinetic energy just before it is launched, as measured by (i) an observer riding on the cart and (ii) an observer standing on the ground.
(b) Compute the block’s translational kinetic energy just after it is launched, again as measured by (i) the cart observer and (ii) the ground observer.
(c) For each observer, determine the change in the block’s translational kinetic energy caused by the spring. State whether both observers agree on the value of the energy transferred by the spring and explain your reasoning.