Question

A light inextensible string that goes over a smooth fixed pulley as shown in the figure connects two blocks of masses 0.36 kg and 0.72 kg. Taking \( g = 10 \, \text{m/s}^2 \), find the work done (in joules) by the string on the block of mass 0.36 kg during the first second after the system is released from rest. 

• A. 4 J
• B. 8 J
• C. 6 J
• D. 10 J

Hint:

Work done by a force is given by \( W = F \cdot d \), where \( F \) is the force applied and \( d \) is the displacement.

Answer 1

The Correct Option is C

Step 1: Analyze the system.
Both blocks will accelerate downward and upward, respectively, with the same acceleration due to the tension in the string. The net force on the block of mass 0.36 kg is \( F = m g - T \), and the work done is \( W = F \cdot d \).
Step 2: Calculate the work done on the block of mass 0.36 kg.
The total acceleration of the system can be calculated and used to find the displacement of the block over the first second. The work done is found to be 8 J. Final Answer: \[ \boxed{8 \, \text{J}} \]