JEE Main Physics question
If we throw a body upwards with a velocity of 4 m/s, at what height does its kinetic energy reduce to half of the initial value? (Taking g = 10 ms⁻¹)
Answer: (D)
Solution
Initial KE = ½m(4)² = 8m. At height h, KE = 4m (half the initial value), which equals the PE gained: mgh = 4m ⟹ h = 4/g = 4/10 = 0.4 m.