Question

please help guys....

Answer 1

force of friction = uN = umg = -0.2 x 50 x 10 = -100
work done by friction = -100 x 100 = -10000 joules

Answer 2

•Frictional force=uN=umg=0.2×50×10=100N; •here, u is (MU) a sign; coefficient of friction.
•work done=-F.S= -100×100=-10000=-(10)^4 J.
•If force has a component in the direction opposite to the displacement, the force does negative work done.