Concepts Of Physics MCQ Edition [Volume 1]PhysicsWork and Energy
Zero work is performed by a force on an object if
Options
- Athe force remains perpendicular to its acceleration at all times
- Bthe force remains perpendicular to its velocity at all times
- Cthe object moves such that the point of application of the force remains stationary
- Dthe object stays stationary while the point of application of the force moves along the object
Correct answer
D. the object stays stationary while the point of application of the force moves along the object
Step-by-step solution
The work done by a force on an object is defined as W = F d r , where d r is the displacement of the material point of the object at which the force acts. If the force is perpendicular to the acceleration, it is not necessarily perpendicular to the velocity. For instance, a force acting on a particle moving with a velocity that has components both parallel and perpendicular to the force can still do work, even if the net acceleration is purely perpendicular to the force. Hence, work is not guaranteed to be zero in