A pool can be filled by a pipe in 3 hours. it takes 3 times as long for another pipe to empty the pool. how long will it take to fill the pool if both pipes are open?

The water that powers the generators enters and leaves the system at a low speed (thus we can neglect its change of kinetic energy) and loses 160 m of altitude during the process.

A pulley system lifts a 500-lb. block 2.0 feet with an effort of only 50 lb. If the 50 lb. moves 30 feet, calculate the efficiency of the pulley system.

A child runs at speed vc while an adult runs at speed va. if the adult gives the child a head start of distance d, how long will it take for the adult to catch the child? express your answer in terms of va and vc and d.

A world class sprinter is travelling with speed 12.0 m/s at the end of a 100 meter race. Suppose he decelerates at the rate of 2.00 m/s^2. (a) How long does it take him to come to a stop? (b) How far does he travel as he is stopping?

How is energy conserved in:pushing a car uphill

What can you do to reduce the electric uses within your home?

The impulse experienced by a body is equivalent to the body's change in A) velocity B) kinetic energy C) momentum D) force

Does the system's kinetic energy increase, decrease, or stay the same? or is there not enough information to tell?

How do inertia and centripetal force combine to keep an object moving in circular motion?

Compare and contrast the average kinetic energy of 0.5 L of coffee at 34°C, 0.5 L of coffee at 38°C, and 0.25 L of tea at 43°C.