An object with a mass of #7# #kg# is hanging from an axle with a radius of #36# #m#. If the wheel attached to the axle has a radius of #9# #m#, how much force must be applied to the wheel to keep the object from falling?

1 Answer
Feb 22, 2016

Answer:

This is a similar case to a lever: the torque on both sides need to be the same for balance. #tau_1=rF=rmg=36*7*9.8=2469.6# #Nm#. #tau_2=rF to F=tau_2/r# but #tau_1=tau_2# so #F=2469.6/9=274.4# #N#.

Explanation:

I think the explanation above is clear, but it's worth pointing out that the force acting one the #7# #kg# mass is its weight force, #F=mg# where #g# is the acceleration due to gravity, #9.8# #ms^-2#.