A mystery surprise box is sliding down a ramp at a constant speed. The box has a mass of 55.0kg and the ramp makes a 40.0œ angle with the horizontal. What is the coefficient of kinetic friction between the box and the ramp?

Question

A mystery surprise box is sliding	down a ramp at a constant speed.	 The box	has a mass of 55.0kg and the ramp makes a 40.0œ angle with the horizontal. What is the coefficient of kinetic friction between	the box and the ramp?

Please help asap. Thank you.

Henry · Answer

Wb = M*g = 55 * 9.8 = 539 N.

Fp = 539*sin40 = 347 N. = Force parallel
to the ramp.

Fn = 539*Cos40 = 413 N. = Normal force.

Fp-Fk = M*a.
347-Fk = M*0 = 0.
Fk = 347 N. = Force of kinetic friction.

u = Fk/Fn.