A 1380 kg block is being pulled across the floor by a rope which is wrapped around a motorized winch. The coefficient of kinetic friction between the block and the floor is 0.41, and the block moves at a constant speed of 1.34 m/s. What is the power output of the motor, in Watts

1. A spring is used to stop a 50-kg package that is moving down a 20° incline. The spring has a constant k = 300 N/cm, and is held by cables so that it is initially compressed 5 cm. If the package is moving at 2 m/s when it is 8 m from contacting the spring, what additional deflection in the spring will be required to stop the motion. 2 m/s 50 kg Cable HiiN 20°

A 100 lb force exerted against a 1000-lb block causes the block to slide with constant velocity. The friction force on the block must be

An electric motor that is 98% efficient runs off of a 100 W power supply.  What is the maximum speed the motor could lift a 10 kg mass straight up?  What is the maximum speed the motor could move the 10 kg mass across a frictionless surface?  (This second question can only be answered in terms of the force that the motor applies to the mass.  So, I should have added something like:  Assume the electric motor is attached to the mass by a cable that has a maximum force tension of 3 kN.)