# Mechanics (Power): Calculate Horizontal Resistive Force

• Kajan thana
In summary, at a constant speed of 55 m s–1, the useful power output of the motors is 22 kW and the horizontal resistive force acting on the vehicle is 400N. The net force acting on the vehicle is zero, which means that the driving force is equal to the 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]

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?

What is the net force acting on the vehicle?

cnh1995 said:
What is the net force acting on the vehicle?
I don't know the net force.

Kajan thana said:
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
cnh1995 said:
What do you know about the net force from this?
it is zero

Kajan thana said:
it is zero
Yes.
So driving force=resistive force.

Kajan thana
cnh1995 said:
Yes.
So driving force=resistive force.
Thank you.

## 1. What is horizontal resistive force in mechanics?

Horizontal resistive force, also known as frictional force, is the force that opposes the motion of an object sliding or rolling along a surface. It acts in the opposite direction of the object's motion and is dependent on the surface characteristics and the weight of the object.

## 2. How is horizontal resistive force calculated?

Horizontal resistive force can be calculated using the formula F = μN, where F is the resistive force, μ is the coefficient of friction, and N is the normal force (equal to the weight of the object).

## 3. What factors affect the magnitude of horizontal resistive force?

The magnitude of horizontal resistive force is affected by the coefficient of friction, the normal force, and the surface characteristics of the object and the surface it is moving on. Other factors such as the speed and temperature can also have an impact.

## 4. How does horizontal resistive force affect an object's motion?

Horizontal resistive force acts to slow down or stop an object's motion, as it works in the opposite direction of the object's motion. This force can also cause an object to change direction or slide in a different direction.

## 5. Can horizontal resistive force be reduced or eliminated?

Horizontal resistive force can be reduced by using lubricants, such as oil or grease, which can decrease the coefficient of friction. It can also be eliminated by using wheels or other mechanisms to reduce the surface area in contact with the surface, thus reducing the normal force and friction.

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