A man shoveling snow clears his front step using 200 joules in 100 seconds. How much power did he use? 300 watts
2 watts
20,000 watts
100 watts

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Which sound characteristic is not affected by the relative motion of an object

Consider lifting a box of mass m to a height h using two different methods: lifting the box directly or lifting the box using a pulley (as in the previous part). what is wd/wp, the ratio of the work done lifting the box directly to the work done lifting the box with a pulley?