One car has two and a half times the mass of a second car, but only half as much kinetic energy. When both cars increase their speed by 7.0 m/s, they then have the same kinetic energy. What were the original speeds of the two cars?(adsbygoogle = window.adsbygoogle || []).push({});

let x = mass of second car

thus mass of first car = 2.5x

let a = speed of first car

let b = speed of Second car

0.5 * 2.5x * (a+7)^2 = 0.5 * x * (b+7)^2 (equation 1)

2 * 0.5 * 2.5x * a^2 = 0.5 * x * b^2

2.5x * a^2 = 0.5 * x * b^2 (equation)

0.5 * 2.5x * (a+7)^2 = 0.5 * x * (b+7)^2 (equation 1)

2 * 0.5 * 2.5x * a^2 = 0.5 * x * b^2

2.5x * a^2 = 0.5 * x * b^2 (equation 2)

Herre are the equations I got, but didn't get the right answers still. Help anyone?

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# Homework Help: Finding the Velocities

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