The kinetic energy of an object of mass, m moving with a velocity

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The kinetic energy of an object of mass, m moving with a velocity of 5 ms-1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?

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Kinetic energy, k = $\frac{1}{2}$ mv2.
Where m = mass of the object
V = velocity of the object.
Here mass (m) is the same in both cases (∵ object is same)
$\frac{k_1}{k_2}=(\frac{v_1}{v_2})^2$
Initial kinetic energy k1 = 25J
Initial velocity V2 = 5 ms-1
New kinetic Energy K2 = ?
New velocity v2 = 3v1 = 3 × 5 = 10 ms-1

∴ When velocity is increased three times its K.E. is 225 J.

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