Consider the motion of a rock tied to a string of length 0.50 m. The string is s
ID: 1319174 • Letter: C
Question
Consider the motion of a rock tied to a string of length 0.50 m. The string is spun so that the rock travels in a vertical circle as shown in the figure below. The mass of the rock is 1.5 kg, and it is twirling at constant speed with a period of 0.23 s.
(b) What is the total force on the rock directed toward the center of the circle? (Enter the magnitude only.)
___________N
(c) Find the tension in the string when the rock is at the top and when it is at the bottom of the circle. (Enter magnitudes only.)
Explanation / Answer
m = 1.5 kg
mg = weight of rock = (1.5)(9.8) = 14.7 N
R = 0.50 m
T = 0.23 s means that the angular velocity of the rock = 2?/0.23 = 27.3 rad/s = w
The Centripetal Force = Fc = mV