posted by Mei Lei on .
1. You slowly lift a book of mass 2 kg at a constant velocity a distance of 3 m. How much work did you do on the book?
I got 180 for this
2. A 15 kg crate is moved along a horizontal floor with a rope that makes a 30 degree angle with the horizontal. If the tension in the rope is 200 N and the crate is slid 10 meters, how much work has been done on the crate?
3. True or False: An object that is motionless has no energy
4. What is the kinetic energy of a ball of mass .1 kg traveling at a speed of 160 m/s?
5. Assuming air resistance is zero (negligible), how high up would a .06 kg tennis ball travel if hit straight into the air at initial speed of 50 m/s?
6. A stunt woman scales a 40 meter high cliff. What is her potential energy due to gravity relative to the ground?
7. Imagine you are 100 kg and standing at the edge of a hole that goes to the center of the earth. What is your potential energy relative to the center of the earth?
1. The work done is W = M g H
H is the distance it is lifted
You need to review the definitions of potential and kinetic energy and make an effort on the other questions.