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by Ron Kurtus

A total of 120 comments and questions have been sent in. They are listed according to date.

## List of next 10 letters

### Country

Friction Equation Friction on inclined surface Nigeria

Resistive Force of Friction Forces involved in stopping a moving trian India

Resistive Force of Friction Does friction obey Newton's Law? USA

Resistive Force of Friction Friction resistance Malaysia

Friction Equation Formula of finding the coefficient of friction Kenya

Friction Equation Firction with rubber sandwiched betwwen two plates South Africa

Uses of Friction Applications of friction Nigeria

Rolling Friction Needs derivation for rolling friction Singapore

Rolling Friction and Automobile Tires Effect of tread patterns in traction USA

Friction Feedback Detemine coefficient of friction South Africa

Next 10

First 10 letters

## Friction on inclined surface

Topic: Friction Equation

### Question

May 22, 2014

If a question is being given to solve applying either static ir kinetic friction formula. How would I start solving. For example: an object of mass, 10Kg is placed on an incline plane at 30 degree to the horizontal. Calculate (i) the reaction between two surfaces (ii) coefficient of static friction. [g = 10m/s] how can I start solving?

zion - Nigeria

24984

See Sliding Friction and Sliding Friction on an Inclined Surface to get information to help solve the problem.

I hope that helps.

## Forces involved in stopping a moving trian

Topic: Resistive Force of Friction

### Question

May 14, 2014

First of all I would like to thank you for helping me immensely in my studies with your easy to understand concepts. I have a question. Could you please tell me what are the forces that stop a train when approaches a platform??
Thanking You

Ishika - India

24955

Stopping a train at the platform is somewhat complex. When the brakes are applied to the wheels, the friction force must be sufficient to slow the train but not so much as to lock the wheels. If the brakes lock the wheels, the iron wheels will slide on the track, reducing their friction. It is better that the wheels slow down without sliding, such that the train will slow more effectively.

The total force required to stop the train is its mass times the change in velocity divided by the time required to stop the train.

Of course, the weight of the train (mass * g) affects the friction on the tracks.

I hope those concepts help.

## Does friction obey Newton's Law?

Topic: Resistive Force of Friction

### Question

April 2, 2014

Is the frictional forces are action-reaction forces,does they obey newton third laws

- USA

24836

When you push on an object, friction causes an equal and opposite force pushing on you, according to Newton's Law.

## Friction resistance

Topic: Resistive Force of Friction

### Question

March 25, 2014

FRICTION_________THE DIRECTION OF MOVEMENT OF AN OBJECT.

LINGKESHWARAN - Malaysia

24810

Resists

## Formula of finding the coefficient of friction

Topic: Friction Equation

### Question

November 6, 2013

Please send me all the formulas of finding the coefficient of friction

orina - Kenya

24176

The coefficient of friction between two specific materials is found experimentally. Using the equation fr = F/N where fr is to coefficient of friction, F is the force required to move one object over the other, and N is the normal force pressing the objects together, you can find fr, if you know F and N.

## Firction with rubber sandwiched betwwen two plates

Topic: Friction Equation

### Question

November 1, 2013

Would the friction coefficient of rubber on steel double up if the rubber was sandwiched between two steel plates and a force applied to the upper steel plate?

Steel plates are stationary, rubber can be pulled out.

Tony - South Africa

24156

The frictional resistance to motion would double because you have friction on two surfaces. The coefficient of friction for rubber and steel would remain the same for each surface.

## Applications of friction

Topic: Uses of Friction

### Question

October 28, 2013

how can one discuse the various area where friction is applicable and what are the problem in designing elements or components

john - Nigeria

24140

You can look around you an see many areas were friction is needed to hold things or to slow down motion. Also, in cases of moving objects, such as a vehicle, reducing friction is desirable.

## Needs derivation for rolling friction

Topic: Rolling Friction

### Question

May 18, 2013

Hello,

I am a high school student and I am writing a research paper in IB and I need to figure out the frictional force acting on a rolling bar of copper on two rails of aluminium. To do this, I need to figure out the coefficient of rolling friction. I understand that the equation to figure out the coefficient is on the web page but, my teacher asked me to find a derivation of the formula. I have searched many books and websites but I cannot seem to find it anywhere. If it is not to much to ask, would it be possible for you to show me how the equation: ¼R = v/(tg) is derived?

Thank you

Alto - Singapore

23699

The equations for rolling friction seem to be empirical or from experiments. I've never seen a derivation of the equations.

One resource that might help you is Rolling friction and rolling resistance.

Rolling Resistance also gives some information that may apply.

I hope this helps in your paper. Best wishes for success.

## Effect of tread patterns in traction

Topic: Rolling Friction and Automobile Tires

### Question

April 16, 2013

Hello,
My name is Zach. I'm researching tires and friction for a physics project and you seem like you would have some knowledge on the topic. Can you give me a few sentences of information about how you think tire tread patterns and materials used for tires effect the friction in different driving environments.
Look back to hearing from you soon!

Zach - USA

23623

The tread pattern of a tire affects the traction in wet, snowy, or muddy conditions. For example, some tread patterns are meant to push road water away, so that the tire will not hydroplane on the road.

On a dry concrete or asphalt road, the treads of a tire actually increase the rolling friction. Thus, a good compromise needs to be made.

Studded tires help traction in icy conditions, but they do not provide good traction on dry streets.

I hope that helps.

## Detemine coefficient of friction

Topic: Friction Feedback

### Question

February 9, 2013

I am doing a practical report. It is based on Determining the coefficient of static friction. I am asking how to draw a free body diagram which will show all the forces acting on the block before it starts to move and after it start to move. Please help me

Nkuthalo - South Africa

23190

If you have a rope tied to a block and pull parallel to the ground, the only forces will be the force on the rope, the resiting friction force and the weight of the block toward the ground.

However, if you putt the rope slightly upward, you will still have the same forces, but they will have different values because you are pulling slightly upward.

Sorry that I can't send diagrams.

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## Summary

Observe friction in action

## Resources and references

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