A boy of mass 40kg is climbing a vertical pole at a constant speed.If the coefficient of friction between his palms and the pole is 0.8 and `g=10m/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 the horizontal force that the boy is applying on the pole. The various forces that are acting on the boy is shown in the figure. Frictional force, `f= mu N = mg `
` or N = (mg)/(( mu ) = ( 40 xx 10)/( 0.8 ) =500 N`
therefore F=N = 500 N`