A boy of mass 40 kg is climbing on a vertical pole at a constant speed. If the coefficient of friction between his palms and the pole is 0.8 and g = `10 m//s^(2)`, the horizontal force that he is applying on the pole is

Options

A. 300 N
B. 400 N
C. 500 N
D. 600 N

Answer

C

Explanation

Here,`mu`= 0.8
Let F be horizontal force that the boy is applying on the pole. The various forces are acting on the boy as shown in the figure.
Frictional force,f= μN= mg
`N=(mg)/(mu)=(40xx10)/(0.8)=500N`
F=N=500N