One car has twice the mass of a second car, but only half as much kinetic energy. When both cars increase their speed by 8.5 m/s, they then have the same kinetic energy. What were the original speeds of the two cars?(adsbygoogle = window.adsbygoogle || []).push({});

first i set it up like this:

.5 * m * v1^2 = .5 * (.5 * 2m * v2^2)

then i get:

v1 = v2

then

.5 * m * (v1 + 8.5)^2 = .5 * 2m * (v2 + 8.5)^2

.5 * (v1 + 8.5)^2 = (v2 + 8.5)^2

but its not right...

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# Homework Help: Kinetic Energy speed and a car

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