A stone is dropped from a tower reaches ground in 4 s. Height of tower (g=10) is MCQ with Answer and Explanation

Explanation:
3 half-lives => 1/8.

Explanation:
KE ∝ p². Double KE ⇒ p_new = √2 p_old ⇒ increase = (√2 - 1)×100% ≈ 41.4%. Memory tip: 'KE ∝ p²; %Δp ≈ ½ %ΔKE for small changes, but use exact for large'. Energy-momentum relation frequently tested in competitive exams.

Explanation:
In free fall under gravity alone, mechanical energy (kinetic + potential) is conserved, assuming no air resistance. Potential energy decreases while kinetic energy increases, sum constant. Law of conservation of mechanical energy. Non-conservative forces absent.