Question

A body of mass 2kg is thrown upward with initial velocity of 20m/sec. after 2 seconds, its kinetic energy will be : (g = 10m/sec2)

Answer 1

We will use the following equation of motion to get the final velocity after 2 seconds.

V = u - gt

U = 20 m/s

g = 10

t = 2

V = 20 - 2 × 10

V = 20 - 20

V = 0

K.E = 1/2mv²

m = 2

v = 0

K.E = 0.5 × 0 × 2 = 0

= 0

Answer 2

A body of mass 2 kg is thrown skyward with original velocity of 20 m/sec and after 2 seconds, its kinetic energy will be g = 10m/sec2.

IT can be  calculated as follows Potential energy =m  * g  * h.

So it is =2 × 20 × 10 joules and = 400 joules .