Question

33. A body of 2 kg falls from rest. What will be its kinetic energy during the fall at the end of
2 s? (Assume g = 10 m/s-)​

Answer 1

Given,

mass of body =2kg

time taken =2s

we know,

v = gt

v = 10 x 2

v = 20m/s

K. E = 1/2mv²

= 1/2 x 2 x 20 x 20 = 400J

So, kinetic energy of body =400J

⚡⚡Hope this helps ✌✌

Answer 2

Solution :-

As per the given data ,

• Mass of the body(m) = 2 kg

• Initial velocity (u) = 0 m/s ( rest )

• Time taken ( t) = 2 sec
• Acceleration due to gravity (g) = 10 m/s ²

As the body is moving uniformly under the influence of gravity we can use the first kinematic equation to find the final velocity of the body at the end of 2 s

Hence ,

⇒ v = u + gt

Now let's substitute the given value in the above equation ,

⇒ v = 0 + 10 x 2

⇒ v = 20 m /s

We know that ,

⇒ KE = m v ² / 2

⇒ KE = 2 x 400 / 2

⇒ KE = 400 J

The kinetic energy of the body at the end of 2 s is 400 J