In the Cavendish balance apparatus shown in the figure below, suppose that m_1 =
ID: 1568947 • Letter: I
Question
In the Cavendish balance apparatus shown in the figure below, suppose that m_1 = 1.02 kg, m_2 = 26.3 k and the rod connecting the pairs is 28.8 cm long. (a) If, in each pair, m_1 and m_2 are 11.0 cm apart, find the net force. (b) If, in each pair, m_1 and m_2 are 11.0 cm apart, find the net torque about the rotation axis) on the rotating part of the apparatus. (c) Does it seem that the torque in part (b) would be enough to easily rotate the rod? Yes No Suggest some ways to improve the sensitivity of this experiment.Explanation / Answer
a )
given
m1 = 1.02 kg ,
m2 = 26.3 kg ,
L = 28.8 cm
F = G m1 m2 / r2
F = 6.67 X 10-11 X 1.02 X 26.3 / 0.112
F = 1.47 X 10-7 N
b )
L = 0.288 / 2 = 0.144 m
torque is T = 2 F g L
T = 2 X 1.47 X 10-7 X 0.144
T = 4.2336 X 10-8 N.m
c )
Answer is NO
because torque is very very small
so will not rotate...