The kinetic energy of a car is 1.02 × 105 J. If the car s speed increases by 28.2%, then what is the new kinetic energy of the car?

I set up the ratio Kf/Ki=Vf2/Vi2

Vf= 1 + 28.2/100)2Vi2

this cancels the right side of the equation out to (1.282)2

to find Kf, I then multiplied both sides by Ki, making the left side (1.282)2X10,200

this means Kf=16764J

Why is this incorrect?

I set up the ratio Kf/Ki=Vf2/Vi2

Vf= 1 + 28.2/100)2Vi2

this cancels the right side of the equation out to (1.282)2

to find Kf, I then multiplied both sides by Ki, making the left side (1.282)2X10,200

this means Kf=16764J

Why is this incorrect?

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