Question

An inextensible cable of negligible mass is used to drag a log on a rough horizontal surface. The tension in the cable is 850 N and it acts at an angle of 35° to the horizontal. The log is dragged over a distance of 45m. The frictional force experienced by the log is 150 N. a) Define the term work. b) Calculate the net work done on the log. 

Answer 1

a) Define the term work: this is a physical quantity that shows how much energy was transferred to or from a system by applying a force along some path.

b) The net work is

$$W=Td\text{ cos}\theta=850·45·\text{cos}35º=31300\text{ J}.$$