Work Done & Friction: Definition & Effect

In summary, the concept of work done can be defined as F x distance moved in the direction of the force. When considering a moving car, friction can either do positive or negative work depending on the direction of the car's motion and the direction of the force. If the car is accelerating, the force and motion will be in the same direction, resulting in positive work. However, when braking, the force and motion will be in opposite directions, causing negative work to be done. The direction of friction is dependent on whether the car is accelerating or decelerating, as it acts to oppose slipping between surfaces.
  • #1
Griff38
8
0
If work done is defined as F X distance moved in the direction of this force, is friction doing work on a moving car since if the car is moving to the right friction is actually acting to the left? or should the definition of work done be F x distance moved parallel to the line of action of this force in which case the displacement and force can be in totally opposite directions.
 
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  • #2
If the car moves to the right but friction acts to the left, then the work done will be negative. That would be the case when braking. If the car is accelerating, then the force will point in the direction of motion and the work done will be positive.
 
  • #3
Thank you so much, that's made it very clear.
 
  • #4
Consider a car moving forward to the right as you look at the car. This implies the the tires rotating in a clockwise direction. As a point on the tire comes around to the bottom where it contacts the road, the direction the tire is moving relative to the road is to the left. Friction, in this case, is then applied to the tire toward the right --> in the direction of the cars motion. As previously mentioned, friction acts opposite to the direction of motion. The "motion" being the motion of the tire.
 
  • #5
The direction of friction depends on whether the car is accelerating or deaccelerating. Friction acts to oppose slipping between the surfaces.
 

1. What is work done?

Work done is the measure of energy transferred when a force acts on an object and causes it to move in the direction of the force.

2. How is work done calculated?

Work done is calculated by multiplying the force applied to an object by the distance the object moves in the direction of the force.

3. What is friction?

Friction is the force that opposes the motion of an object when it comes into contact with another surface. It is caused by the roughness of surfaces and can be affected by factors such as weight and surface area.

4. How does friction affect work done?

Friction acts in the opposite direction of the force applied to an object, making it more difficult to move the object and thus decreasing the amount of work done.

5. Can friction be beneficial?

Yes, friction can be beneficial in situations such as walking or driving, where it provides necessary traction and prevents slipping. It can also be used to slow down or stop objects in motion, such as in the case of brakes on a car.

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