Question

a stone of mass 200g falls from a height of 5m with a velocity of 1.5m. assuming g=10m/s, calculate the
1]potential energy
2]kinetic energy
3]velocity
just before hitting the ground

Answer 1

1]potential energy
p.e=mgh
m=200g, convert by dividing, 200 divided by 1000=0.2kg
g=10
h=5m
0.2kg x 10 x 5=10j

2]kinetic energy
k.e=1/2 mv2
m=0.2
v=1.5
=1/2 x 0.2 x 1.5
=1/2 x 0.2 x 2.25
=1/2 x 0.45
=0.225j
3]velocity
v=gh=1/2 v2
gh/1=v2/2
gh x2=2gh, v2 x1=v2
v2=2gh
v2=2 x 10 x 5
v2=100
v=100[square root]
v=10m/s