Answer to Question #162994 in Mechanics | Relativity for Sage Topaz

Question

A 100 kg wooden crate, at rest, is pushed across a horizontal floor with a force of 400 N. The coefficient of kinetic friction between the surfaces is 0.4, find the work done in pushing this crate 70 m. How much work went into overcoming friction?

Answer 1

Solution:

If we ASSUME that the pushing force is applied horizontally:

a) Find the work done in pushing this crate 70 m

W = Fd = 400(70) = 28000 J

b) How much work went into overcoming friction?

W = Fd = μmgd = 0.4(100)(9.8)(70) = 27,440 J