Question

In the adjoining figure, two pulses in a stretched string are shown. If initially their centres are 8 cm apart and they are moving towards each other, with speed of 2 cm/s, then total energy of the pulses after 2 s will be

• A. Zero
• B. Purely kinetic
• C. Purely potential
• D. Partly kinetic and partly potential

Hint:

When two pulses in a string meet, the total energy is conserved and is purely kinetic if there is no reflection.

Answer 1

The Correct Option is B

Step 1: Analyzing the motion of the pulses.
Since the pulses are moving towards each other, they will collide after 2 seconds. The total energy of the system will be purely kinetic at that point.

Step 2: Conclusion.
The total energy of the pulses after 2 seconds will be purely kinetic, which corresponds to option (2).