Pushing force vs. Friction force

In summary, when an object is pushed with a force while moving at a constant velocity, there is an equal and opposite friction force acting on it. This does not mean the object will come to a complete stop, as a net force of zero only implies zero acceleration, not zero velocity. Once the pushing force exceeds the friction force, the object will accelerate from rest and continue to move at a constant velocity.
  • #1
RobinSky
112
0
My teacher in mechanics says that when we have a force pushing an object (moving at constant velocity) forward we also have a friction force that equals to the force that is pushing the object. So if we call the friction force for Fr and the pushing force for F, F=Fr.

But in my mind, when we have 2 forces in opposite directions the object is standing still. So if my teacher is correct, how am I thinking wrong? Or can any give some tips to solve this fault of thinking.

Regards, Robin Andersson
 
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  • #2
RobinSky said:
But in my mind, when we have 2 forces in opposite directions the object is standing still.
Your teacher is correct. Your error is in thinking that a net force of zero implies zero velocity. What it does imply is zero acceleration. If the net force is zero, then the velocity will be constant, not necessarily zero.
 
  • #3
In other words, once the pushing force exceeds the force of friction, the object accelerates from rest until the friction force and pushing force are equal...from then on constant velocity ensues.
 

Related to Pushing force vs. Friction force

1. What is the difference between pushing force and friction force?

Pushing force is the force applied to an object in order to move it, while friction force is the resistance force that opposes the motion of the object. Pushing force is an external force, while friction force is an internal force.

2. How does the amount of pushing force affect friction force?

The amount of pushing force applied to an object can directly affect the amount of friction force experienced by the object. As the pushing force increases, the friction force also increases. This is because the greater the force applied, the more resistance the object will encounter while trying to move.

3. What factors affect the friction force of an object?

The friction force of an object can be affected by several factors, including the type of surface the object is moving on, the weight of the object, and the speed at which the object is moving. The rougher the surface, the heavier the object, and the faster the speed, the greater the friction force will be.

4. How does friction force impact the movement of objects?

Friction force can have both positive and negative impacts on the movement of objects. On one hand, it can prevent objects from slipping or sliding, providing stability and control. On the other hand, it can also slow down or impede the movement of objects, requiring more force to overcome.

5. How can the effects of friction force be reduced?

The effects of friction force can be reduced by using lubricants, such as oil or grease, to create a smoother surface between two objects. Additionally, reducing the weight of an object or using smoother surfaces can also help to decrease friction force. Additionally, minimizing the contact area between two objects can also reduce the friction force experienced.

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