Question

A body of mass 2 kg is thrown vertically upwards with an initial velocity of 20 m /s .What will be it's potential energy at the end of 2s???(Assume ---g=10m/s^2)

Answer 1

Helloo!!

Given,
u = 20 m/s
a = -10 m/s^2
t = 2 sec!

then,
h = 20x2-1/2x10x2^2
= 20 m

PE = mgh
= 2x10x20
= 400 j

hope it helps!!

Answer 2

HEY DEAR.....!!



let at height ‘h’ kinetic energy will become half

using law of conservation of energy

(potential nergy at height ‘h’) + (kinetic energy at height ‘h’) = initial kinetic energy

mgh + 1/2 (K) = K
here K is initial kinetic energy which is 245 J 

 mgh = 1/2 (K) as K = 245        
mgh = 1/2 (245) as m = 2 kg   and g = 9.8  m/s2 

so, h = 6.25 m

HOPE IT'S HELP U ☺