how to determine kinetic friction?

how to determine kinetic friction?



2 Answers

Aman Bansal
592 Points
12 years ago

Dear Anil,

When an object rests on an inclined plane, a component of its weight is supported by the ramp as a force normal (perpendicular) to the ramp, and a component of its weight is acting parallel with the ramp in the downward direction. Use sin and cos to find the components of the weight that are acting normal and parallel to the ramp.

The component parallel to the ramp is the force that will cause acceleration down the ramp. But since we are told there is friction, we know that this force will be opposed by the kinetic friction sliding down the ramp. So, per Newton's Second Law, the sum of the forces acting on the box is equal to the mass times acceleration of the box.

So now we have a formula that relates the sum of the forces acting on the box with the acceleration. And we know the gravitational component of the force from above, so now all we need is the frictional component of the force acting on the box. See the link below for the formula for friction. And we already know the normal force from above. So now we can put everything together into one formula and solve for mu.

This can be solved without knowing the weight of the box because once you combine all parts of the formula into one you can see that the mass appears on both sides of the formula, so it can be removed by dividing both sides by the mass. The correct answer is given below just so you can check your work, but please go through the steps of forming the equations and showing your work.

Best Of luck

Cracking IIT just got more exciting,It’s not just all about getting assistance from IITians, alongside Target Achievement and Rewards play an important role. ASKIITIANS has it all for you, wherein you get assistance only from IITians for your preparation and winexciting gifts by answering queries in the discussion forums. Reward points 5 + 15 for all those who upload their pic and download the ASKIITIANS Toolbar, just a simple click here to download the toolbar….

So start the brain storming…. become a leader with Elite Expert League ASKIITIANS


Aman Bansal

Askiitian Expert

Godfrey Classic Prince
633 Points
12 years ago



Kinetic friction- the force that opposes relative motion between surfaces in contact. Kinetic friction is friction applied to a moving object. This is the opposite of static friction which applies to a non-moving object

Hopw you understood it now..

Please approve my answer if you liked it by clicking on "Yes" given below...!!!Smile

Think You Can Provide A Better Answer ?


Get your questions answered by the expert for free