Question

В
7.9 - CP A small rock with mass Figure E7.9
0.20 kg is released from rest
at point A, which is at the top
edge of a large, hemispherical
bowl with radius R = 0.50 m
(Fig. E7.9). Assume that the
size of the rock is small com-
pared to R, so that the rock can
be treated as a particle, and assume that the rock slides rather than
rolls. The work done by friction on the rock when it moves from
point A to point B at the bottom of the bowl has magnitude 0.22 J.
(a) Between points A and B, how much work is done on the rock
by (i) the normal force and (ii) gravity?​

Answer 1

Answer:

no work done by

Explanation:

Between points A and B, how much work is done on the rock by the normal force? 

-There is no work done by the normal force because all of the work is being done by gravity. 

W=0J 

Between points A and B, how much work is done on the rock by gravity? 

-Work done by gravity is just the gravitational potential energy lost by moving in the vertical direction, so you use the equation Wg=mgh. In this case, h is just the radius so I'll sub that instead 

Wg=mgR 

Wg=(.26)*(9.8)*(.50) 

Wg=1.274 J