In the figure below, a small block of mass m = 0.021 kg can slide along the fric
ID: 1519608 • Letter: I
Question
In the figure below, a small block of mass m = 0.021 kg can slide along the frictionless loop-the-loop, with loop radius R = 15 cm. The block is released from rest at point P, at height h = 6.7 R above the bottom of the loop. How much work does the gravitational force do on the block as the block travels from point P to point Q? How much work does the gravitational force do on the block as the block travels from point P to the top of the loop? If the gravitational potential energy of the block-Earth system is taken to be zero at the bottom of the loop. And the following. the potential energy when the block is at point P the potential energy when the block is at point Q the potential energy when the block is at the top of the loop 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? increase decrease remain the sameExplanation / Answer
The first thing to do is determine the height of point P in meters.
h = 6.7* 0.15 = 1.005 m
Let’s use this number to determine the block’s potential energy at point P.
PE = 0.021 * 9.8 * 1.005 = 0.206829 J
The next step is to determine the block’s potential energy at point Q. At point Q, its height is 0.15 m.
PE = 0.021 * 9.8 * 0.15 = 0.03087 J
(a) How much work does the gravitational force do on the block as the block travels from point P to point Q?
The work is equal to the difference of the two potential energies.
Work = 0.206829 – 0.03087 = 0.175959 N * m
(b) How much work does the gravitational force do on the block as the block travels from point P to the top of the loop?
At the top of the loop, the block’s height is 0.3 m.
PE = 0.021 * 9.8 * 0.3 = 0.06174 J
The work is equal to the difference of the block’s initial potential energy and this number.
Work = 0.206829 – 0.06174 = 0.145089 N * m
(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 point P?
This was my first answer.
(d) What is the potential energy when the block is at point Q?
This was my second answer.
(e) What is the potential energy when the block is at the top of the loop?
This was my third answer.