# power as it relates to constant velocity but increasing speed

by student1984
Tags: constant, force, instantaneous power, power, velocity
 P: 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?
Mentor
P: 11,907
Welcome to Physics Forums.
 Quote by student1984 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?
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.)

 Related Discussions Introductory Physics Homework 8 Introductory Physics Homework 2 Introductory Physics Homework 4 Introductory Physics Homework 2 Classical Physics 8