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Calculating the corresponding percentage

  • Thread starter adam640
  • Start date
  • #1
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Homework Statement



A car is travelling at initial speed 5.5ms-1. The car is on a decline of 8o. The brakes are used and the car stops after travelling 10m along the road (with no skidding).

At the moment when kinetic energy is 51% lower than the initial value,
find the corresponding percentage fall in speed.


Homework Equations


Ek = 1/2mv2


The Attempt at a Solution


E is 51% lower, so [tex]\frac{2(0.49)Ek}{m}[/tex]=v2
Clueless?!
 

Answers and Replies

  • #2
verty
Homework Helper
2,164
198
Start with

[tex]\frac{Ek_2}{Ek_1}=\frac{49}{100}[/tex]

From that relationship, get a relationship between the two velocities.
 

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