What is the speed of the crate when it reaches the bottom?

  • Thread starter physx_420
  • Start date
  • #1
33
0

Homework Statement


A 20.0-kg crate slides down an inclined plane that is 3.00-m high and 20.0-m long. If friction is negligible, what is the speed of the crate when it reaches the bottom of the plane?



Homework Equations


W= F*D
K= 1/2 m*(v^2)


The Attempt at a Solution


They don't give me an angle so I'm not sure how I'm supposed to go about solving for the force parallel to the inclined plane. Once I have that I'll be able to finish out the problem. Help please!
(The answer turns out to be 7.67 m/s; I just need to know how to get there)
 

Answers and Replies

  • #2
56
0
Just use conservation of energy. You have gravitational potential energy in the beginning. Don't bother with the work [tex]W=FD[/tex].
 
  • #3
33
0
Ahhh, ok I see. Thanks alot N-gin!
 
  • #4
60
0
The 20 M long is not needed for this problem because the friction is assumed to be zero. No energy is lost in friction and so M*g*H = (1/2)*M*V^2

So V = sqrt(2*g*H)

So the velocity is independent of the Mass!!!

If you had friction, then still mass is irrelevant.
 

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