Question

A mass of 2.63 kg is attached to a string tied to a hook in the ceiling. The length of the string, L, is 0.8 m, and the mass is released from rest at an initial position in which the string makes an angle θ of 40.4o with the vertical. Calculate the work (in J) done by gravity by the time the string is in a vertical position for the first time.

Answer 1

work done by gravity = change in potential energy in falling from initial height

h = L (1-cos theta)

h = .8 (1 - cos 40.4)

so work=m g h = 2.63*9.8*.8 (1 - cos 40.4)