I am having some trouble with a couple of physics h/w problems and would appreciate any help you can give me..(adsbygoogle = window.adsbygoogle || []).push({});

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!]

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Help with a couple physics problems

**Physics Forums | Science Articles, Homework Help, Discussion**