Minimum ramp height for a ball to complete a loop with radius 0.3 m

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mailmas
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Homework Statement


What minimum height does the frictionless ramp have to be for the ball to be able to travel along the ramp into a loop upside down and not fall?
Radius of loop = .3m

Homework Equations


PE + KE = PE + KE

The Attempt at a Solution


mgh_1=mgh_2 + 1/2 mv^2
h_1 = h_2 + v^2/(2g)

h_2 = .3m[/B]
Am I on the right track?
 

Discussion

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Is there a picture that goes with the question? If there is, please post it.
 
kuruman said:
Is there a picture that goes with the question? If there is, please post it.
No :(
 
If this is a "loop-the-loop" problem (as I suspect) then your solution is incorrect. If the ball starts at a height equal to the radius, then it can only rise to the same height of 0.3 meters on the other side and slide back. Energy conservation is part of the solution. The other part is that the ball must have enough speed at the top of the loop. How much speed is "enough" must be determined with a free body diagram, which is the remaining part of the solution. Even if you don't have a picture, you need to draw one in order to see what's going on.
 
kuruman said:
If this is a "loop-the-loop" problem (as I suspect) then your solution is incorrect. If the ball starts at a height equal to the radius, then it can only rise to the same height of 0.3 meters on the other side and slide back. Energy conservation is part of the solution. The other part is that the ball must have enough speed at the top of the loop. How much speed is "enough" must be determined with a free body diagram, which is the remaining part of the solution. Even if you don't have a picture, you need to draw one in order to see what's going on.

Would speed be determined by: FN = mv^2/r - mg = 0
 
mailmas said:
Would speed be determined by: FN = mv^2/r - mg = 0
Yes.