posted by shay on .
The tops of the towers of the golden gate bridge in san Francisco, are 227m above the water. suppose a worker drops a 655g wrench from the top of a tower. if the average force of air resistance is 2.20 percent of the force of free fall what will the kinetic energy of the wrench be when it hits the water?
I suppose that what they are calling the "force of free fall" is the weight, M g.
Frictional work performed against air resistance while falling will then be
0.022 M g H
Subtract that from M g H to get the kinetic energy when it hits the water.
(1/2) M V^2 = 0.978 M g H