# Example of kinetic force > static force

• PCSL
In summary, kinetic force can be greater than static force in cases such as when an object is traveling faster than 0.866c or when there is drag on an object moving through a fluid or gas. However, there are also cases where static and kinetic forces are close, such as with teflon on teflon. Additionally, control mechanisms may use a fluid to increase resistance with speed, but this is not a clear example of static versus dynamic friction. Further discussions on this topic can be found on online forums.
PCSL
Can someone give me an example of a case where kinetic force would be greater than static force? Thanks.

Any object traveling faster than 0.866c will possesses kinetic energy greater than it's own rest energy (if this is what is meant btw).

If I understand your question correctly then friction would be an example of a static force. It exists regardless of whether an object is moving or not. Drag would be an example of a kinetic force. It is only experienced by objects that are moving through a fluid or gas. As to whether one is greater than the other that depends on the situation.

Can someone give me an example of a case where kinetic force would be greater than static force? Thanks

I expect you are referring to impact forces.

In general a static force is a resistance between two forces.

static force = mass
inottoe said:
Any object traveling faster than 0.866c will possesses kinetic energy greater than it's own rest energy (if this is what is meant btw).

static force = friction
Skateboard going down hill.

static force = tensile strength
A weight that breaks a rope used to suspend it.

static force = shear strength
Scissors cutting paper.

static force = gravity
An airplane in flight.

I'm an idiot, I apologize. I meant friction.

So to rephrase my question: Can someone please provide an example where kinetic friction > static friction.

PCSL said:
Can someone please provide an example where kinetic friction > static friction.
I'm not aware of any solids that have this behavior, although the static and kinetic friction can be close for some cases, like teflon on teflon, with a coefficient of about 0.4 for both.

There are control mechanisms called slide rails that use a fluid between the rail and a slider. The presence of the fluid results in resistance to movement that increases with speed, to elminate jerky movements for precise control. Some of these maintain the fluid by pumping the fluid through holes in the rail. This isn't really a case of static versus dynamic friction though.

rcgldr said:
I'm not aware of any solids that have this behavior, although the static and kinetic friction can be close for some cases, like teflon on teflon, with a coefficient of about 0.4 for both.

There are control mechanisms called slide rails that use a fluid between the rail and a slider. The presence of the fluid results in resistance to movement that increases with speed, to elminate jerky movements for precise control. Some of these maintain the fluid by pumping the fluid through holes in the rail. This isn't really a case of static versus dynamic friction though.

Thank you.

## 1. What is the difference between kinetic force and static force?

Kinetic force is a type of force that is associated with objects in motion, while static force is a type of force that is associated with objects at rest. In other words, kinetic force is the force required to keep an object in motion, while static force is the force required to prevent an object from moving.

## 2. Can you provide an example of kinetic force?

One example of kinetic force is the force exerted on a ball as it rolls down a hill. The force of gravity pulls the ball down the hill, and the force of friction between the ball and the ground is the kinetic force that keeps the ball in motion.

## 3. How does kinetic force affect an object's velocity?

Kinetic force can change an object's velocity by either increasing or decreasing it. When a force is applied in the same direction as an object's motion, it will increase the object's velocity. On the other hand, when a force is applied in the opposite direction of an object's motion, it will decrease the object's velocity.

## 4. What is an example of static force?

An example of static force is the force that a person exerts on a wall when pushing against it. The wall is not moving, so the force exerted by the person is a static force. Another example is the force of gravity pulling an object towards the ground when it is resting on a surface.

## 5. How does the magnitude of kinetic force compare to that of static force?

The magnitude of kinetic force is typically greater than that of static force. This is because kinetic force is required to overcome the force of friction and keep an object in motion, while static force only needs to counteract the force of gravity to keep an object at rest.

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