(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A block slides on a rough horizontal surface from point A to point B with a force of magnitude 2 newtons acts on the block between points A and B. Points A and B are 1.5m apart. If the KE of the block at A is 5 joules, and KE at B is 4J, how much work is done on the block by the force of friction as the block moves from A to B

my crude rendering of said block:

http://img69.imageshack.us/img69/2411/30326150.th.png [Broken]

2. Relevant equations

change in E mechanical=Work done by other forces - Force of friction * distance

3. The attempt at a solution

change in KE = Force * distance + Work done by friction

-1 = 2 cos 40 * 1.5 + Work done by friction

-1 = 2.29813 + Work done by friction

-3.298J = Work done by friction

is this correct?

i got -3.298J

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Block Slides on Rough Horiz Surface with Pic

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