1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Energy problem.

  1. Oct 13, 2008 #1
    1. The problem statement, all variables and given/known data

    A daredevil on a motorcycle leaves the end of a ramp with a speed of 39.5 m/s as in Figure P5.23. If his speed is 38.0 m/s when he reaches the peak of the path, what is the maximum height that he reaches? Ignore friction and air resistance.

    2. Relevant equations

    Eo = mgy

    Ek = 1/2mv^2

    3. The attempt at a solution

    I don't even know where to begin. I need someone to cue me on what equation i should be using because frankly I can't even fathom. I thought perhaps Eo=Ek, but I'm not sure if this is it.
  2. jcsd
  3. Oct 13, 2008 #2
    Alright so in the begining the motocycle has Ek only; however, when it reaches the top it gains some Ep therefore some Ek is transformed into Ep due to conservation of energy.



    Ep = mgy

    Ek = 1/2mv^2


    1/2m(39.5)^2 = 1/2m(38)^2 + m(9.8)y

    Now u can cross out the ms by factoring m from both sides and deviding boths sides by m.
    1/2(39.5)^2 = 1/2(38)^2 + (9.8)y

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook