Question

pls answer urgently req. A body of mass 2kg if thrown vertically upwards with initial velocity 20m/s.What will be its potential energy at the end of 2s.

Answer 1

u = 20m/s
g = 9.8m/s
t = 2 sec

h = ut+(1/2)gt^2
= 20×2 + (1/2)×-9.8×(2)^2
= 40 - 19.6
= 20.4 m

m = 2kg

P.E = mgh
= 2×9.8×20.4
= 399.84 J

Answer 2

Given :
u = 20m/S
g = 10m/s^2
t = 2s

H = ut - 1/2gt^2
H = 20 x 2 - 1/2 x 10 x 4
H = 40 - 20
H = 20m

Now m = 2kg
g = 10m/s^2
H = 20m

Potential energy = mgH
= 2 x 10 x 20
= 400 J