How long does it take to stop the car

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To determine the stopping distance of a car moving at 14 m/s with a coefficient of friction of 0.8, one must first create a free-body diagram (FBD) to identify the forces acting on the vehicle, including weight, friction, and normal force. The analysis focuses on the forces in the positive X direction, leading to the equation 4f=ma, where f represents the friction force. By solving for acceleration (a) and applying the kinematic equation Vf^2=Vi^2+2*a*d, with the final velocity (Vf) set to zero, the stopping distance (d) can be calculated. A tutorial is available for further guidance on this process. Understanding these principles is essential for accurately determining stopping distances in physics.
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if a car is moving at 14m/s, and the coefficient of friction is 0.8, what is the distance it takes to stop the car after the brakes are applied locking all four wheels?
 
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The first step in the problem is to draw your free-body diagram and label all of the forces acting on the car.
Basically you have 3 forces, the force of the weight, the force of friction, and the normal force on each tire.
Because each of these forces are the same on each wheel it is only neccesary to draw the FBD for one wheel.
After you draw your FBD set up your force equation in each direction. In this case the car is is only moving in 1 direction call it the positive X direction.
So you have your sum of the forces in the X direction equation.
4f=ma
where is the friction force

solve that equation for a and then use the kinematic equation Vf^2=Vi^2+2*a*d

with Vf=0 solve for d
 
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