I am having problems with the kinetic energy formula KE = 1/2 mv^2.(adsbygoogle = window.adsbygoogle || []).push({});

If an object of 1kg travels at a speed of 1ms its kinetic energy is 1/2 * 1 * 1^2 = 0.5J.

But if it collides with an object of 0.5kg which is stationary, to conserve momentum which is equal to mass * velocity = 1 * 1 = 1kgms the new speed of the 0.5kg object = momentum / mass = 1/0.5 = 2ms. The kinetic energy of this new object is equal to 1/2 * 0.5 * 2^2 = 1/4 * 4 = 1J. This is double the energy of the initial object which is impossible. It does not make sense to me that the faster an object travels a disproportionate amount of energy is required. I think that the origin of KE (1/2 mv^2), the integration of F=ma, is something that cannot be integrated in reality, only in theory, if momentum is to be conserved.

Can anyone shed any light on this?

Thanks

Stephen Lewis

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# Kinetic Energy and Momentum

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