A horizontal force of 150 N is used to push a 33.0-kg packing crate a distance of 5.70 m on a rough horizontal surface. ?

Question

A horizontal force of 150 N is used to push a 33.0-kg packing crate a distance of 5.70 m on a rough horizontal surface. If the crate moves at constant speed, find each of the following.

(a) the work done by the 150-N force

 J

(b) the coefficient of kinetic friction between the crate and the surface

Answer 1

a) Work done is Force x distance moved

i.e. 150 x 5.7 = 855 Joules

b) Using F = ma we have:150 - Friction = 33(0)...acceleration is zero as velocity is constant.so, friction force is 150 NewtonsNow, Friction = µ.R =>  µ(33g)Hence, µ(33g) = 150so, µ = 150/33g => 0.46 :)> 

Answer 2

work = Fd = 150•33 = ____ J

weight = 33•9.8

coef friction µ = 150/33•9.8 = ____