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Homework Help: Car of mass m travelling down a motorway

  1. Apr 22, 2012 #1
    2. A car of mass m travelling down the motorway at 100 km/hr suddenly stops pressing the accelerator pedal. The result is that the car slows to 60 km/hr in ten seconds. Suppose all travel is along a level road.
    (a) What is the average force acting on the car serving to slow it's motion?
    (b) How much power is required to maintain the car at 100 km/hr given this external force?
    (c) How much more energy is done in travelling at 105 km/hr than 100 km/hr? To how much petrol might this correspond?
  2. jcsd
  3. Apr 22, 2012 #2
    Please show us your attempt at a solution, then we can help you.
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