Which of the following statements about a body under equilibrium is/are correct ?
- 1. No forces are acting.
- 2. A number of parallel forces may be acting.
- 3. The law of moments must apply.
Select the correct answer using the code given below :
1, 2 and 3
2 and 3 only
1 and 3 only
2 only
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CISF-AC-EXE – 2018
Statement 1: “No forces are acting” is incorrect. Forces can be acting, but they must be balanced, meaning the vector sum of all forces is zero.
Statement 2: “A number of parallel forces may be acting” is correct. For example, if two equal and opposite parallel forces act on a body, they form a couple, which produces a torque. For the body to be in equilibrium, this torque must be balanced by other torques, and the net force must be zero (which these two forces satisfy). More generally, parallel forces can sum to zero net force and zero net torque.
Statement 3: “The law of moments must apply” is correct. The Law of Moments states that for rotational equilibrium, the sum of clockwise moments about any point equals the sum of anticlockwise moments about the same point. This is a necessary condition for a body to be in equilibrium.