Mechanics (Power): Calculate Horizontal Resistive Force

[Kajan thana]

Homework Statement

The vehicle now accelerates to a constant speed of 55 m s–1. The useful power output of the motors is 22 kW at this speed.

Calculate the horizontal resistive force acting on the vehicle?
[/B]

Homework Equations

P=FV

The Attempt at a Solution

:

F=P/V[/B]
so the answer is 400N

But what I do not understand is why are we using that formula and how do we know that is the resistive force?

 

[cnh1995]

What is the net force acting on the vehicle?

 

[Kajan thana]

What is the net force acting on the vehicle?

I don't know the net force.

 

[cnh1995]

The vehicle now accelerates to a constant speed of 55 m s–1.

What do you know about the net force from this?

 

[Kajan thana]

What do you know about the net force from this?

it is zero

 

[cnh1995]

it is zero

Yes.
So driving force=resistive force.

 

[Kajan thana]

Yes.
So driving force=resistive force.

Thank you.