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

Answer:

#~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#