Question

A is double the mass of another ball B. the ball A moves at half speed of ball B. calculate the ratio of kinetic energy of A to the kinetic energy of B?

Answer 1

see the photo for your answer

Answer 2

Let mass of ball A be '2m' and mass of ball B be 'm' ----(given).
Let the velocity of ball A be 'v' and velocity of ball B be '2v' ----(given).
Now,
Since KE = 1/2mv^2
Therefore, KE of ball A = 1/2*(2m)*(v)^2 -----(1)
And KE of ball B = 1/2*(m) *(2v)^2 ----(2)
Now, ratio of KE's of both balls,
=> (KE of ball A)/(KE of ball B)
=> [1/2*(2m)*(v)^2]/[1/2*(m)*(2v)^2]
=> 2/4
=> 1/2
Therefore, ratio of KE of ball A to ball B is 1 : 2 (answer)



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