Question

A 4.0-kg block starts from rest and slides 5.0 m down a plane inclined at 60 degrees to the horizontal. The coefficient of kinetic friction between the surface and the block is 0.20. The work done by friction on the block is

A) 98.0 J
B) 19.6 J
C) 3.92 J
D) 3.40 J
E) 64.0 J

Answer 1

C

Step-by-step explanation:

Friction=coefficient of kinetic Friction ×normal force.In this case the normal force is equal to mg.You going to say mg×coefficient of kinetic Friction you will get Frictional force. Use the Frictional force to calculate work done by friction you get -3.92J.Then you can say the work done on the object by friction is 3.92J.