If you push a lawn mower across a yard in 10 seconds, how does the work done compare with pushing it across the same yard in 20 seconds? Explain why.

If you push a lawn mower across a yard in 10 seconds, how does the work done compare with pushing it across the same yard in 20 seconds? Explain why.
How does the power for 10 seconds compare to the power for 20 seconds?
How many kilometers per liter will a car obtain if its engine is 25 percent efficient and it encounters an average force of 1000 Newtons? Assume the energy content of gasoline is 40,000,000 joules per liter (J/L).