Friction and Acceleration problem?

In summary, the driver of an automobile traveling at a speed of 15.8 m/s locked the wheels by slamming on the brakes, with a coefficient of kinetic friction between the tires and the road of 0.760. After 1.10 s, the speed of the automobile can be calculated by using the formula Ffr = (mu)(FN), with FN = (mass)(g). However, in this case, there is no mass given to calculate the normal force. Another approach is using the equation a = -mu g, which can be derived from the equation Ffr = -mu m g = -m a. From there, ordinary kinematics can be used to find the speed of the automobile after 1.
  • #1
bman123
5
0
1. Traveling at a speed of 15.8 m/s, the driver of an automobile suddenly locks the wheels by slamming on the brakes. The coefficient of kinetic friction between the tires and the road is 0.760. What is the speed of the automobile after 1.10 s have elapsed? Ignore the effects of air resistance



2. Ffr=(mu)(FN)
FN=(mass)(g)



3. There is no mass to calculate the normal force. I tried multiplying the acceleration times the friction coefficient and dividing that by the time elapsed but can't get the right answer. ANy help?
 
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  • #2
Well, friction = [tex]\mu m g = -m a \implies a = -\mu g[/tex].

Now can you use ordinary kinematics to get the rest of the answer?
 

FAQ: Friction and Acceleration problem?

What is friction and how does it affect acceleration?

Friction is a force that occurs when two surfaces come into contact and move against each other. It acts in the opposite direction of motion and can decrease the speed of an object. This decrease in speed ultimately affects the acceleration of the object.

How is friction measured?

Friction is measured using a unit called the coefficient of friction, which is a ratio of the force of friction and the normal force (the force exerted by the surface on the object).

Can friction help or hinder acceleration?

Friction can both help and hinder acceleration. When an object is moving on a surface with friction, the friction force acts in the opposite direction of motion and can decrease the object's acceleration. However, in some cases, friction can also provide the necessary force to increase an object's acceleration, such as in the case of a car's tires gripping the road to propel the car forward.

How does the type of surface affect friction and acceleration?

The type of surface can greatly affect friction and acceleration. Rough surfaces tend to have higher coefficients of friction, resulting in greater friction force and decreased acceleration. On the other hand, smooth surfaces have lower coefficients of friction, resulting in less friction force and potentially increased acceleration.

How can friction be reduced to increase acceleration?

The most effective way to reduce friction and increase acceleration is by using a lubricant, such as oil or grease, to smooth out the surface and reduce the coefficient of friction. Additionally, using smoother surfaces or reducing the weight of the object can also decrease friction and increase acceleration.

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