7. Imagine a small rocket engine is attached to the rock. How much work is done by the rocket engines to move the rock from: a) 2R, to 6R, b) R. to infinity

11. Can a normal force on an object ever do work on the object? Explain.

You push a shopping cart a certain distance with a certain force. If you apply that same force, but push the shopping cart TWICE the distance as in the first case, the work you do in this second case is _________ as the work done in the first case.   a. the same amount.   b. four times as much.   c. half as much.   d. twice as much.

11. How much work does Amanda's car experience compared to Bertha's? Amanda and Bertha are in a car race. Their cars have the same mass. At one point in the race, they both change their speeds by 10 m/s in 2 seconds. Ignore air friction. 2s later 2s later 10 m/s 20 m/s 20 m/s 30 m/s Amanda Bertha a. Amanda's car experiences less work b. Amanda's and Bertha's car experience the same amount of work c. Amanda's car experiences more work. O d. Only Rihanna would know. (Work Work Work Work Work...) 96 alt

5). Which requires more work, pushing a 200 kg refrigerator up a ramp into a truck, or lifting it straight up and setting it in the truck? Explain.

6. Two blocks are connected by a very light string passing over a massless, frictionless pulley (see figure). Traveling at a constant speed, the 20.0-N block moves 65.0 cm to the right and the 12.0-N block moves 65.0 cm down. How much work is done a. on the 12.0-N block by gravity? b. on the 12.0-N block by the tension in the string? in total on the 12.0-N block? C. d. on the 20.0-N block by gravity? on the 20.0-N block by the tension in the string? on the 20.0-N block by the normal force? on the 20.0-N block by friction? in total on the 20.0-N block? e. f. g. h. 20.0 N 12.0 N

2. Mikey sees that the right front tire (m 30.0 kg) of Granny's car has landed in front of him. He picks it up and runs for 40 m at a constant velocity of 2.0 m/s to return it to her. How much work did Mikey do on the tire from 10 m to 20 m into his run? =

4.) Worker 1 lifts a mass M1=30kg straight up a distance of 4 meters in 9 seconds. Worker 2 lifts a mass M2 = 15kg straight up a distance of 3 meters is 2 seconds. Determine: a.) Which worker did more work? b.) Which worker developed more power?

A particle moves 5 m in the +x direction while being acted upon by a constant force F = 2i + 5j– k N. The work (in Joules) done on the particle by this force is Select one: O a. 16 O b. -5 O c. 12 O d. 25 O e. 10

Please help me with this question:  1. Bob a man with a mass of 90kg, climbs up a 3.5m high tree. a.) How much work must Bob do in order to make it to the top of the tree, assuming that he begins and ends at rest?    Bob now jumps out of the tree and land on the ground.  b.) How fast will he be going just before he hits the ground?   c.) First assume that he forgets to bend his knees. That means that he wil land hard - the cushions on his feet will make him move downward 1.6cm while coming to a stop, but that's it. How much force will he feel from the ground while he stops?    d.) As you can see, that enormous force result in a everely injured Bob. So rewind, and let's assum Bob bends his knees this time. That means that the ground forced is in contact with him while he moves 0.45cm downward. Now how much force will the ground exert on Bob?