A balanced lever has two weights on it, the first with mass 1 kg and the second with mass 7 kg. If the first weight is 8 m from the fulcrum, how far is the second weight from the fulcrum?

1 Answer
Mar 12, 2018

~1.14 meters

Explanation:

When a lever is balanced, the torque exerted on either side of the fulcrum is equal, so the lever is held in equilibrium.

tau = rFsintheta where tau is the torque on one side of the lever and theta is the angle that the side makes with the fulcrum.

tau_1 = (1*9.8) * 8 * 1
tau_2 = (7*9.8) * r * 1

Knowing that tau_1 and tau_2 are equal, we can combine the two equations to solve for r.

9.8 * 8 = 68.6r
78.4 = 68.6r
r = 1.14