Power as it relates to constant velocity but increasing speed

  1. the questions I have are general questions regarding power and velocity

    here are some relevant equations:
    P=Fv

    a) if the force required to keep an object in motion with a constant velocity does not depend on the speed of the object, does the power required to keep the object moving in at a constant velocity increase, decrease or remain the same with increasing speed?

    b) in actuality, the force required to keep a car moving with a constant velocity increases in magnitude with the square of the car's speed. Does the power required to keep the car moving with a constant velocity increase, decrease or remain the same with increasing speed? How does this result compare with the answer to question a?

    I'm assuming from that answer to part a is REMAIN THE SAME and part b is INCREASES WITH INCREASING SPEED.

    am i correct in my assumptions?
     
    Last edited: Nov 1, 2011
  2. jcsd
  3. Redbelly98

    Redbelly98 12,031
    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to Physics Forums.
    If the velocity is constant, then the speed must be constant also. (The velocity's magnitude and direction are both constant; speed is the magnitude of velocity, hence it is constant.)
     
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