Question

During the swinging of a simple pendulum,

• A. The work done by tension force is always zero
• B. The work done by the gravitational force is zero
• C. The mechanical energy of the bob remains constant in the presence of air resistance
• D. The mechanical energy of the bob does not remain constant in the absence of air

Answer 1

The correct option is A The work done by tension force is always zero

Since tension force is always perpendicular to the direction of instantaneous displacement of the bob, the work done due to tension force is always zero. Hence, the correct answer is option (a).