A 60kg man takes 5 seconds to run up a set of stairs at a constant velocity. What was the mans power? 15m Mass = 60kg Work is transferred to gravitational potential Energy
A man pushes a 12kg crate horizontally with a constant velocity of 2m/s. The coefficient of friction between the crate and the floor is 0.25. What power does the man have as he pushes the crate? -120N 120N F f
A crane hoist lifts a load of 1000kg a vertical distance of 25m in 9.0s at a constant velocity. What is the useful power output of the crane?
If the hoist motor of the previous crane is rated at 70hp, what percentage of this power goes to useful work?
Efficiency – A measure of what you get out for what you put in. The Efficiency of a typical car is about 25%!
The motor of an electric drill with an efficiency of 80% has a power of input of 600 W. How much useful work is done by the drill in a time of 30 seconds?