How do you solve this problem?
A ball on the end of a string is revolved at a uniform rate in a vertical circle radius of 72.0 cm, as shown in figure. If its speed is 4.00m/s and its mass is .300 kg. Calculate the tension in the string when the ball is a) at the top of the path, and b). when it's at the bottom?
a) Mg + T = MV^2/R
T = M(V^2/R -g)
b) T - Mg = MV^2/R
T = M(V^2/R + g)
T is the tension that you want to compute.
Make sure R is in meters when you do the calculation. The force will be in Newtons.
If the answers to a and b answers are interchanged, your book may be wrong.
All you have to do is use the formulas provided, using these variables:
V = 4.0 m/s
M = 0.3 kg
g = 9.8 m/s^2
R = 0.72 m