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Work-energy theorem.

  • Thread starter ms.cupcake
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  • #1
10kg block is pulled up an incline plane at 30 degree with horizontal in distance 5.0m by force 120N.coefficient of kinetic energy 0.4.

help!how do you get the velocity of block? answer: v=3.48ms^-1
 

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  • #2
rude man
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Are you looking for the velocity at 5m with velocity = 0 at 0m? Or what?
 
  • #3
the velocity of the block after it has move 5m up the plane
 
  • #4
Doc Al
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10kg block is pulled up an incline plane at 30 degree with horizontal in distance 5.0m by force 120N.coefficient of kinetic energy 0.4.
I assume you meant that the coefficient of kinetic friction is 0.4.

So what does the work-energy theorem say? What forces are acting on the block? How much work do they do?
 
  • #5
*correction- kinetic friction*.
frictional force,the gravitational force,applied force and normal force.The work done by gravitational force=-245.25J,energy lost by overcoming friction=-169.92J,work done by force,120N=600J, and the total work done i found was 184.83J. so how do I get the velocity of the block after it has move 5m up the plane?
 
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  • #6
Doc Al
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*correction- kinetic friction*.
frictional force,the gravitational force,applied force and normal force.The work done by gravitational force=-245.25J,energy lost by overcoming friction=-169.92J,work done by force,120N=600J, and the total work done i found was 184.83J. so how do I get the velocity of the block after it has move 5m up the plane?
Assuming you've calculated the total work correctly, use the work-energy theorem! Total Work = ΔKE.
 
  • #7
Doc Al
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10kg block is pulled up an incline plane at 30 degree with horizontal in distance 5.0m by force 120N.coefficient of kinetic energy 0.4.

help!how do you get the velocity of block? answer: v=3.48ms^-1
I don't see how you can get that answer from the given data.

Is the applied force parallel to the incline?

If this from a textbook, tell me which book and problem.
 
  • #8
applied force is parallel.
and no its not from txtbook
 
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  • #9
rude man
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*correction- kinetic friction*.
frictional force,the gravitational force,applied force and normal force.The work done by gravitational force=-245.25J,energy lost by overcoming friction=-169.92J,work done by force,120N=600J, and the total work done i found was 184.83J. so how do I get the velocity of the block after it has move 5m up the plane?
work in = friction loss + gain in potential energy + gain in kinetic energy.

You are very close to solving this problem. Your numbers agree with mine. So where do the 185 J go at the top of the ramp?

BTW I believe the given answer is wrong if v = 0 at the bottom of the ramp.
 

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