A smooth wooden block is placed on a smooth wooden tabletop. You must exert a 14.0N force to keep the 40.0N block moving at constant velocity. a. What is the coefficient of sliding friction?
b. If a 20.0N brick is placed on the block, what force will be required to keep the block and brick moving at constant velocity?

How much work is done lifting a 9.10 kg box straight up onto a shelf that is 1.80 m high?

The slope of a velocity time graph over any interval of time gives the during that interval

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.