Work, Force, and Brakes: Solving the Physics Problem

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AI Thread Summary
The discussion revolves around solving a physics problem related to a car's braking system. Participants are tasked with calculating the work done by the brakes, the average force applied, the stopping distance if the speed is doubled, and the power developed by the brakes. One user expresses confusion and seeks guidance, prompting others to suggest starting with the definition of work and using kinematic equations to find acceleration and force. The conversation emphasizes collaborative problem-solving and encourages sharing calculations for further assistance. Overall, the thread highlights the importance of understanding fundamental physics concepts to tackle the homework questions effectively.
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Homework Statement



Use this information to answer the next 4 questions: The brakes of a 1452 kg car bring it to a stop from a speed of 17.2 m/s in a distance of 100 m.



Homework Equations



15. How much work do the brakes do?
2.15 x 105 J
1.42 x 106 J
2.50 x 106 J
7.12 x 105 J


16. What average force do the brakes apply?
2.50 x 104 N
7.12 x 103 N
2.15 x 103 N
1.42 x 104 N


17. How much distance would the car cover as it stops if the speed were doubled? Assume that the average braking force remains constant.
400 m
100 m
200 m
800 m


18. If the car originally stops in 6.2 s (100 m), what power is developed by the brakes?
23.4 kW
2.15 kW
34.7 kW
230 kW



The Attempt at a Solution


I am so lost and I don't even know where to start with these. If you can help me I will be so grateful!
 
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hi laurenbaboran! :wink:

let's start with #15:

what is the definition of work done?

what theorems do you know about work done?​

one of those two answers should give you a quick way of answering #15 :smile:
 
Just use the standard equations of kinematics.
Calculate the acceleration of car first.
Use it to find force.
Use that to find work.
:wink:
(EDIT:crossed posts with tiny-tim and his shiny new avatar :smile:)
 
Okey dokey thanks for the help :) Sorry to spam up the forum thread! I am SO bad at physics!
 
laurenbaboran said:
Sorry to spam up the forum thread!

No, that's what it's there for! :wink:

Show us what you get :smile:
 
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