A fountain pumps 550 gallons of water per minute to a height of 15 m in the air.  If one gallon of water has a mass of 3.79 kg, determine the power necessary to operate this fountain.

A man pushes a lawn mower on a level lawn with a force of 211 N. If 52% of this force is directed forward, and 53 W of power is expended in pushing the mower 7.0 m, how much time is spent in pushing the mower this distance?

A hummingbird hovers by exerting a downward force on the air equal, on average, to its weight. By Newton's third law, the air exerts an upward force of the same magnitude on the bird's wings. Find the average mechanical power (in W) delivered by a 3.60 g hummingbird while hovering if its wings beat 75.0 times per second through a stroke 3.98 cm long. HINT To find the average power per stroke, calculate the work done each stroke and divide by the time per stroke. Click the hint button again to remove this hint.

If a 1300 kg car can accelerate from 30 km/h to 65 km/h in 4.0 s , how long will it take to accelerate from 65 km/h to 95 km/h ? Assume the power stays the same, and neglect frictional losses.