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A car with a mass of 1800 kg slows from 42 km/h [E] to 28 km/h [E].

  • #1

Homework Statement


A car with a mass of 1800 kg slows from 42 km/h [E] to 28 km/h [E]. The impulse from the brakes is?

I know its a simple question but I was hoping if I could get a walkthrough. I keep getting the answer 2.5 x 10^4 N*s [W] and the answer is 7.0 x 10^3 N*s


Homework Equations


p=pf-pi


The Attempt at a Solution


(1800)(28[E])-(1800)(42[E])=50400[E]-75600[E]
=25200[W]
=2.5 x 10^4 N*s [W]
 

Answers and Replies

  • #2
collinsmark
Homework Helper
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Hello CabalGroupie,

Welcome to Physics Forums! :smile:

Homework Statement


A car with a mass of 1800 kg slows from 42 km/h [E] to 28 km/h [E]. The impulse from the brakes is?

I know its a simple question but I was hoping if I could get a walkthrough. I keep getting the answer 2.5 x 10^4 N*s [W] and the answer is 7.0 x 10^3 N*s


Homework Equations


p=pf-pi


The Attempt at a Solution


(1800)(28[E])-(1800)(42[E])=50400[E]-75600[E]
=25200[W]
=2.5 x 10^4 N*s [W]
Don't forget to convert your velocities from kilometers per hour to meters per second. :wink:
 
  • #3
Gahh thank you! I feel so incredibly stupid right now that question bothered me way more then it should have
 

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