NEET2026PhysicsChapterActual
A bullet P of mass 30 g moving with a speed of 200 m/s penetrates a target and comes to rest after travelling a distance of 10 cm inside it. Another bullet Q of mass 20 g moving with a speed of 300 m/s penetrates another target and comes to rest after travelling 20 cm inside it. If F_P and F_Q are the average resistive forces offered by the targets to bullets P and Q respectively, then the ratio F_P F_Q is :
Options
- A3 4
- B4 3
- C2 3
- D2
Correct answer
B. 4 3
Step-by-step solution
Using the work-energy theorem, the work done by the resistive force is equal to the change in kinetic energy of the bullet. F s = 1 2 m u^2 F = m u^2 2 s For bullet P : F_P = 30 10⁻³ (200)^2 2 0.10 = 30 10⁻³ 40000 0.2 = 6000 N For bullet Q : F_Q = 20 10⁻³ (300)^2 2 0.20 = 20 10⁻³ 90000 0.4 = 4500 N The ratio of the average resistive forces is: F_P F_Q = 6000 4500 = 4 3 Answer: 4 3