Question

what are the conditions for an object to be in static equilibrium? a the net force acting on the object and the sum of the torque is zero. b the net force acting on the object and the sum of the torque is non - zero. c the net force acting on the object is non - zero; the sum of the torque is zero. d the net force acting on the object is zero; the sum of the torque is non - zero.

Explanation:

For an object to be in static equilibrium, two main conditions must be met: the net force acting on the object must be zero (so there is no translational acceleration) and the sum of the torques (rotational forces) about any point must also be zero (so there is no rotational acceleration). Let's analyze each option:

• Option A: States the net force is zero and the sum of torque is zero. This matches the conditions for static equilibrium.
• Option B: If net force is non - zero, the object would accelerate translationally, and non - zero torque would cause rotational acceleration, so not in equilibrium.
• Option C: Non - zero net force means translational motion, so not in equilibrium even if torque sum is zero.
• Option D: Zero net force but non - zero torque would cause rotational motion, so not in equilibrium.

Answer:

A. The net force acting on the object and the sum of the torque is zero.