If we throw a body upwards with velocity of 4ms−1 at what height its kinetic energy reduces to half its initial value ? Take g=10m/s2
0.4 m
We know kinetic energy K=12mv2 ∴v∝√K
When kinetic energy of the body reduces to half its velocity becomes v=u√2=4√2=2√2m/s
From the equation v2=u2−2gh⇒(2√2)2=(4)2−2×10h ∴h=16−820=0.4m