Help with a Potential Energy Problem

[champ0342]

In the figure below, a small block of mass m = 1.0 kg can slide along the frictionless loop-the-loop. The block is released from rest at point P, at height h = 8R above the bottom of the loop. (For all parts, answer using g for the acceleration due to gravity, and R and m as appropriate.)
"[URL
http://www.webassign.net/hrw/08_33.gif

(a) How much work does the weight of the block do on the block as the block travels from point P to point Q?

(b) How much work does the weight of the block do on the block as the block travels from point P to the top of the loop?

(c) What is the potential energy when the block is at point P? (Assume that the gravitational potential energy of the block Earth system is taken to be zero at the bottom of the loop.)

(d) What is the potential energy when the block is at point Q?

(e) What is the potential energy when the block is at the top of the loop?

 

[Google_Spider]

Did you read https://www.physicsforums.com/showthread.php?t=94379" ??