Three children slide down a hill.

  • Thread starter pmd28
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  • #1
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Three children, Aaron (20kg), Beth (25kg) and Charlie (30kg) take off on sleds at the top of a hill. Who will reach the bottom first? (μ=.15)
a)Aaron
b)Beth
c)Charlie
d)All of them reach at the same time

f=μN


The answer is d. my first guess was A because i thought that since Aaron had the lowest mass his weight force, and therefore his normal force, would be the smallest; giving him the least amount of resistive frictional force. Why is d correct?
 

Answers and Replies

  • #2
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Find the net force on the body.
Then you can find the acceleration for any mass.
 
  • #3
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but how would I do that if i don't know the [itex]\theta[/itex] of the hill? I drew out my free body diagram but i keep getting stuck when try to resolve the components of the forces.
 
  • #4
1,065
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but how would I do that if i don't know the [itex]\theta[/itex] of the hill? I drew out my free body diagram but i keep getting stuck when try to resolve the components of the forces.

Just put θ as constant for all the cases.
 
  • #5
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:approve:Got it thanks
 

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