I have question regarding work and I was stuck with the wrong solutions. A guy slides a crate up a ramp at angle of 27 deg. by exerting a 285 N force parallet to the ramp. The crate moves at a constant spped. The coefficient of friction is 0.23. How much work did this guy do when the crate was raised a vertical distance of 1.27 m? I started with constant speep. It means that the force 285 N = mg*sin27 + mgcos27*0.23 m = 44.13 kg. delta U = 44.13 * 9.8 * 1.27 = 549 J W = - delta U = - 549 J. The answer was wrong. Can anyone help. Thanks in advance.