In the figure below, a small block of mass m = 0.028 kg can slide along the fric
ID: 2229553 • Letter: I
Question
In the figure below, a small block of massm=0.028kg can slide along the frictionless loop-the-loop, with loop radius13cm. The block is released from rest at pointP, at heighth=16Rabove the bottom of the loop. (For all parts, answer usinggfor the acceleration due to gravity, andRandmas appropriate.)
(a) How much work does the gravitational force do on the block as the block travels from pointPto pointQ?
(b) How much work does the gravitational force do on the block as the block travels from pointPto the top of the loop?
(c) If the gravitational potential energy of the block-Earth system is taken to be zero at the bottom of the loop, what is the potential energy when the block is at pointP?
(d) What is the potential energy when the block is at pointQ?
(e) What is the potential energy when the block is at the top of the loop?
(f) If, instead of being released, the block is given some initial speed downward along the track, do the answers to (a) through (e) increase, decrease, or remain the same?
Explanation / Answer
a) mgh - mg(h - R) = mgR b) mgh - mg(h-2R) = 2mgR c) mgh d) mgR e) 2mgR f) remain same