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Homework Help: Net Force Worksheet

  1. Aug 3, 2009 #1
    1. The problem statement, all variables and given/known data
    A top fuel dragster accelerates at six times the acceleration of gravity. Its mass is 3000kg and it has an initial frictional force of 6000N

    M = 3000kg
    A = 60ms-2 (Lets just say gravity = 10ms-2 down)

    2. Relevant equations
    a) What is the total force?

    b) What is the engine force?

    c) At 300km/h the frictional force has increased to 50,000N, what is its acceleration at this speed?

    3. The attempt at a solution
    a) Fnet = MA
    = 60*3000
    = 180,000N or 180kN

    b) Sorry I have no idea what this is asking for

    c) Sorry I have no idea what this is asking for

    Basically I don't understand what to do in those questions. If anyone could point me in the right direction it'd be greatly appreciated
  2. jcsd
  3. Aug 3, 2009 #2
    How does friction-based propulsion work?
    If you can answer that, the question should become fairly simple.

    Remember Newton's third law, and take into consideration what you do when you walk, you push off the ground, right?

    Try drawing an FBD for the car, and for the FLOOR. The net force on the floor is NOT 0 (Though its acceleration in the direction opposite the movement of the car is completely negligible)
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