Question

a body is moving with uniform velocity of 10 m/s. What will be it's velocity after 2 seconds if no external force acts in the body.​

Answer 1

Explanation:

Given , Mass of object, m=10 kg

Velocity of object, v=20ms

−1

Initial Kinetic energy, K

1

=

2

1

×10×20

2

=2000 J

Now, Final mass, m

2

=20 kg

Final Velocity, v

2

=10m/s

Final Kinetic energy, K

2

=

2

1

×20×10

2

=1000 J

Required Ratio =

K

2

K

1

=

1000

2000

=2:1

Answer 2

2.1

≈2

is the correct answer