# What is the coefficient of kinetic friction for the incline?

1. Jun 17, 2007

### Momentum09

Hi, can someone please give me hints as to how to do this problem?

A 12 kg block is released from rest on an 36 degrees inclined plane and moves 2.4m during the next 4.2s. What is the coefficient of kinetic friction for the incline?

I know that the normal force = mgcos(delta), and dividing this value from the Fs would give me the coefficient, but how do I find this value?

Thank you so much!

2. Jun 17, 2007

### hage567

You need to use Newton's second law. Sum up the forces in each direction (the direction perpendicular to the surface of the incline, and the direction of motion). You will get two equations that will allow you to find the coefficient of kinetic friction. You have been given enough information in the question to find the acceleration of the block down the incline. Have you drawn a diagram and labeled all of the forces present?

By the way, homework questions should be posted in the Homework Forums.

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