Solving Friction Problem - Accelerating Car Without Spilling Coffee

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In summary, the conversation discusses the scenario of a person accidentally leaving a cup of coffee on the roof of their car and driving off. The coefficient of static friction between the coffee cup and the roof of the car is given as 0.24 and the question asks for the maximum acceleration the car can have without the cup sliding. It is also mentioned that the effects of air resistance can be ignored. The second question asks for the minimum time needed to accelerate the car from rest to 20 m/s while keeping the cup on the roof. It is clarified that the mass of the cup is not needed for these calculations.
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hershey1
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Please help...
A person places a cup of coffee on the roof of her car while she dashes back into the house for a forgotten item. When she returns to the car, she hops in and takes off with the coffee cup still on the roof.
(a) If the coefficient of static friction between the coffee cup and the roof of the car is 0.24, what is the maximum acceleration the car can have without causing the cup to slide? Ignore the effects of air resistance.


(b) What is the smallest amount of time in which the person can accelerate the car from rest to 20 m/s and still keep the coffee cup on the roof?

so I don't really even know where to start. How would I know what mu is?
 
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  • #2
How would I know what mu is?

It's given in the question.

What is the equation for the frictional force?

By the way, this is not advanced physics. This should be in the introductory physics forum (for future reference). :smile:
 
  • #3
How much does the cup weigh?

Dont you need its mass?
 
  • #4
No, you don't need the mass. It will cancel out in the end.
 

Related to Solving Friction Problem - Accelerating Car Without Spilling Coffee

What is friction and how does it affect a car's movement?

Friction is a force that resists the motion of an object when it comes into contact with another surface. In the context of a car, friction can affect its movement by creating resistance against the car's tires, making it harder to accelerate or decelerate.

What factors contribute to friction in a car?

There are several factors that contribute to friction in a car, including the type of surface the car is driving on, the condition of the tires, and the speed at which the car is moving. Other factors such as air resistance and the weight of the car can also impact friction.

How can friction be reduced in a car to prevent spilling coffee?

One way to reduce friction in a car is to ensure that the tires are properly inflated and in good condition. Additionally, driving at a slower speed can also reduce the amount of friction. Using a smooth and level road surface can also help decrease friction.

What are some potential solutions for accelerating a car without spilling coffee?

Some potential solutions for accelerating a car without spilling coffee include using a cup holder or securing the coffee cup with a lid or other device. Another solution could be to use a vehicle with a suspension system that minimizes the effects of road bumps and vibrations.

How can understanding friction help with designing more efficient cars?

Understanding friction is crucial in designing more efficient cars because it allows engineers to reduce or control the amount of friction that occurs during the car's movement. By minimizing friction, cars can achieve better fuel efficiency and overall performance.

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