How to find coefficient of friction?

AI Thread Summary
To find the coefficient of friction for a car skidding down an 8% grade hill, one must consider the forces acting on the vehicle, including gravity and friction. The 8% grade translates to a slope angle, which can be calculated using the tangent function. The coefficient of friction, typically between 0.6 and 0.8 for cars, can be determined by applying Newton's second law and kinematic equations. Additionally, converting the speed from 25 MPH to meters per second is necessary for accurate calculations. Understanding these principles will allow for the calculation of the coefficient of friction in this scenario.
Narayanswamy
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If a driver traveling down an 8% grade hill slams down the brakes of his car and skids 30 meters, what is the coefficient of friction ( assuming he was traveling at 25 MPH or more)?

Appreciate your help asap.
 
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you use the acceleration due to gravity and say that the friction overcomes that by ___ amount
 
Last edited:
What is 8% gradient in degrees?
 
is Coefficient of friction tan(slope in degrees) ?
 
i believe that 8% is the tangent of the angle. the coefficient of friction is mu, and for most cars should be between .6 and .8
 
Narayanswamy said:
If a driver traveling down an 8% grade hill slams down the brakes of his car and skids 30 meters, what is the coefficient of friction ( assuming he was traveling at 25 MPH or more)?

Appreciate your help asap.
Assemble the usual suspects: Draw a diagram showing all the forces acting on the car. Apply Newton's 2nd law to relate the net force to the acceleration. Use kinematics or work/energy to compute the acceleration. (Pick a specific speed: convert 25 mph to m/s.)
 
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