- #1
stevo1
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I am having problems with the kinetic energy formula KE = 1/2 mv^2.
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
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