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Homework Help: Power help!

  1. Dec 9, 2008 #1
    1. The problem statement, all variables and given/known data

    I have a physics question that deals with power. In this problem it is of a roller coaster moving from 7m above ground to a point that is 90m above the ground.

    1. What is the power needed for a roller coaster that needs to move 127m and is moving at a velocity of 3.5m/s? The mass of the vehicle is 2375kg and and retarding force on the train is 4225N.

    M= 2375kg
    F= I am not sure if it includes the 4225N or if I need to find it another way
    D= 127

    2. Relevant equations

    Power= Work/Time
    Work= Force * Displacement
    Velocity= change in displacement/ time

    3. The attempt at a solution
    I did 4225*127/ 36.28 but I am not sure if the force is correct or the time....can someone please help!!
  2. jcsd
  3. Dec 9, 2008 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    That is correct if the roller coaster moves along a level track. Yes, the time of 36 seconds is correct.

    If the height of the roller coaster increases, that will require additional energy (and therefore additional power).

    p.s. welcome to PF :smile:
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