Question
The figure shows a ball with mass m = 2.3 kg attached to the end of a thin rod with length L = 0.59 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle. (a) What initial speed must be given the ball so that it reaches the vertically upward position with zero speed? What then is its speed at (b) the lowest point and (c) the point on the right at which the ball is level with the initial point? (d) If the balls mass were doubled, what would the answer to (a) be?
Explanation / Answer
a)
0.5mv2=mgL
AT LOWEST POINT
VLOWEST=sqrt(2gL)
=sqrt(2*9.8*0.59)
=3.4m/s
c)
the point on right at which the ball is level with intial point
here potential energy =0
so velocity equals to 0
d)
velocity of ball does not depend on mass
it has same intial velocity as before