(b) A boy wishes to walk on ice block at a constant speed. The coefficient of sliding friction for steel on ice is 0.05 and the boy weighs 150 N. Find the force required to keep the boy moving at a constant speed along the ice.

Answer 1

M*g = 150 N = Wt. of the boy = Normal force(Fn).

Fk = u*Fn = 0.05 * 150 = 7.5 N. = Force of kinetic friction.

Fap-Fk = M*a
Fap-7.5 = M*0 = 0
Fap = 7.5 N. = Force applied.