Concepts Of Physics MCQ Edition [Volume 1]PhysicsWave Motion and Waves on a String
Consider two waves passing through the same string. The principle of superposition for displacement states that the net displacement of a particle on the string equals the sum of the displacements generated by the two individual waves. Suppose we propose analogous principles for the net velocity and the net kinetic energy of the particle. Such a principle would remain valid for
Options
- Aboth the velocity and the kinetic energy
- Bthe kinetic energy but not the velocity
- Cneither the velocity nor the kinetic energy
- Dthe velocity but not the kinetic energy
Correct answer
D. the velocity but not the kinetic energy
Step-by-step solution
According to the principle of superposition, the net displacement of a particle is given by y = y₁ + y₂ . The net velocity of the particle is the time derivative of the net displacement: v = dy dt = d(y₁ + y₂) dt = dy₁ dt + dy₂ dt = v₁ + v₂ Thus, the principle of superposition is valid for the velocity. The net kinetic energy of the particle is given by: K = 1 2 mv^2 = 1 2 m(v₁ + v₂)^2 = 1 2 m(v₁^2 + v₂^2 + 2v₁v₂) K = K₁ + K₂ + mv₁v₂ Since K K₁ + K₂ , the principle of superposition is not valid for the kinetic ener