One day while moving boxes you get tired and decide to use a rocket instead. You attach a small rocket of negligible mass to a 74.2 kg box. When you turn the rocket on, it provides a constant thrust of 271 N, and the sbox begins sliding across the pavement. If the magnitude of acceleration of the box is 1.72 m/s2, what is the coefficient of kinetic friction between the soapbox and pavement?

Answer 1

resistive friction force = mu m g = mu (74.2)(9.81) = 728 mu
so
271 - 728 mu = 74.2 (1.72)
solve for mu