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The kinetic energy of a 30.0 kg ball is 5.00 X 10^2 J. What is the speed of the ball?

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sherlockholmez | Student, Undergraduate | eNoter

Posted May 3, 2012 at 12:43 AM via web

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The kinetic energy of a 30.0 kg ball is 5.00 X 10^2 J. What is the speed of the ball?

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted May 3, 2012 at 2:20 AM (Answer #1)

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You are allowed to ask only one question per post.

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

Sources:

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sanjeev5757 | High School Teacher | Honors

Posted June 16, 2012 at 6:40 AM (Answer #2)

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kinetic energy E=1/2 M.V^2

Where M is mass of body.

    and V is velocity of body.

as given,M=30Kg.

             E=500J

Putting it to above formula-

                500=1/2.30.v^2

                500=15v^2

                v^2=500/15

                 v^2=100/3

                 v=squrt.(100/3)

                 v=5.77m/s

Hence speed of ball is 5.77m/s.                 

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