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The kinetic energy of a body with a mass m kg and moving at a speed v m/s is given by K.E. = (1/2)*m*v^2 J

The kinetic energy of the ball with a mass 30 kg is 500 J. If the speed of the ball is v, from the equation for kinetic energy given earlier we get:

500 = (1/2)*30*v^2

=> 1000/30 = v^2

=> v = sqrt (100/3)

=> v = 5.774 m/s

The speed of a 30 kg ball with a kinetic energy of 500 J is 5.774 m/s

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