Help with a couple physics problems

AI Thread Summary
Julie is seeking assistance with two physics homework problems involving work and friction. For the first problem, she calculated the work done by her pulling force on a bag but is unsure how to determine the work done by friction and the coefficient of kinetic friction. The second problem involves calculating the time required for a pump to raise a significant amount of water to a cloud's altitude, but confusion arises regarding the use of angles in the power equation. The discussion highlights the challenges of applying physics concepts like work, friction, and power in practical scenarios. Clarification on these topics is essential for solving the problems effectively.
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I am having some trouble with a couple of physics h/w problems and would appreciate any help you can give me..

Julie pulls a 61.5 N bag a distance of 278 m at a constant velocity. The force she exerts is 48.4 N at an angle of 66.8 degrees above the horizontal.
I found the work julie does on the bag to be 5300 J.
Yet I am not sure how to find A) the work done by the force of friction on the bag and B) the coefficient of kinetic friction on the bag

Next problem is
A rain cloud contains 2.82 x 10^7 kg of water vapor.
The acceleration of gravity is 9.81m/s^2
How long would it take a 2.10 kW pump to raise the same amount of water to the cloud's altitude of 1.44km? Answer in seconds (s)
[I tried Power= work(FsCOS[theta]) divided by t. So 2100w=2.82x10^7(9.81)1440m COS 90 degrees DIVIDED by t, which just equals 0 since cos90 is 0. I DONT GET IT!]
 
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why is theta 90? why is this not in the Homework forum?
 
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