Question

two bodies of equal masses are moving with uniform velocities v and 2v.The ratio of their kinetic energy is
a) 1:2
b) 2:1
c) 1:4
d) 4:1​

Answer 1

Answer:

1:2

Explanation:

k.e =1/2 mv2

=1/2mv2

and =mv2(2and 2 get cancel)

ratio is 1:2

Answer 2

Answer:

Let the two bodies be A and B.

Let the mass of:

$\implies$ A be 'm' and B be 'm' 

Note: Since the given masses are equal.

Given:

$\bullet$ Velocity of body A = v

$\bullet$ Velocity of body B = 2v

We know that:

$\boxed{\sf{Ratio\:of\:the\:bodies = \frac{K.E.\:of\:A}{K.E.\:of\:B}}}$

Now:

$\implies$ $\sf{K. E.\:of\:A = \frac{1}{2}mv^{2}}$

$\implies$ $\sf{K. E.\:of\:B = \frac{1}{2}m(2v)^{2}}$

Substituting the above values, we get:

$\implies$ $\sf{\frac{1}{2}mv^{2}}$ / $\sf{\frac{1}{2}m.4v^{2}}$

$\implies$ $\sf{\frac{1}{4}}$

Therefore:

Correct option: c) 1:4

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Answered by: Niki Swar, Goa❤️