Engine power is sometimes expressed in terms of "horsepower." One horsepower was defined by James Watt, who observed that a horse could walk 3.3 km/hr while exerting a nearly constant force of 816 N. (a) What is the conversion for horsepower to kilowatts? (b) If you wanted to run a car just using solar panels, how big an area of solar panels would you need to produce the power of 200 horsepower, used in a car?

A man picks up a 50 kilogram block and carries it up a flight of stairs 10 meters high. He then carries the block back down the stairs and places the block in its original position. What is the NET work done on the block?

You and your friend Gandalf are mowing lawns for extra spending money. Gandalf pushes his mower 25 m and applies a force of 150 N. If you apply a force of 60 N, how far must you push your mower so that the work you do equal Gandalf’s?

Reference: Horsepower Lab. John, of mass 82.4 kg, can do work for about 2.0 minutes at the rate of 1.0 hp. How long will it take him to climb three flights of stairs, a vertical height of 12.0 m?   1hp = 1 horsepower.

A spring has a natural length of 2 ft.  A force of 20 lb stretches the spring to a length of 3 ft.  Find the spring constant.  Then calculate the amount of work done in stretching the spring from its natural length to 3 ft.  How much work is done in stretching the spring from 4 ft to 5 ft.  How far beyond the natural length will a 30 lb force stretch the spring?

A motorist runs out of gas on a level road 170 m from a gas station. The driver pushes the 1,140 kg car to the gas station. If a 190 N force is required to keep the car moving, how much work (in J) does the driver do?

A 1418 kg car can accelerate to 95 km/h in 6.75 s.  What is the average power delivered by the engine?  Hint:  Consider the work energy theorem.  Express your answer in Watts.

A motorist runs out of gas on a level road 210 m from a gas station. The driver pushes the 1,160 kg car to the gas station. If a 190 N force is required to keep the car moving, how much work (in J) does the driver do?

A force of 16 lb is required to hold a spring stretched 2 in. beyond its natural length. How much work W is done in stretching it from its natural length to 8 in. beyond its natural length? write answer as fraction