When is the work done by a constant force on an object zero?
When there is no displacement
Work done by a constant force is \(W = F \times s \times \cos\theta\), where F is the force, s is the displacement of the object and θ is the angle between them.
If there is no displacement (s = 0), then W = F × 0 × cos θ = 0, however large the force. For example, a person pushing hard against a fixed wall does no work on the wall. (Work is also zero when the force is perpendicular to the displacement.)
An unchanged mass, a force applied continuously or a constant speed do not make the work zero: a force applied continuously while the object moves along it does work, and lifting a box at constant speed still needs work against gravity.
Hence, When there is no displacement.
Similar Questions
A stretched rubber band possesses which form of energy due to its changed shape?
Which situation involves an increase in potential energy?
A cart of mass 20 kg starts from rest and accelerates uniformly along a straight horizontal track. If it reaches a speed of 6 m/s in 3 seconds, what is the work done on the cart during this time interval?
What will be the power delivered by a lamp that uses 120 joules of energy in 2 minutes?
When a ball rolls down a hill and comes to rest, how is the total energy of the ball-earth system maintained?
Which of the following quantities is needed to calculate the work done by a constant force?
Which scenario demonstrates a higher power output, assuming the same work is done in each?
Simple machines are best described as devices that _______________.
A body of mass 2 kg kept at the top of a building of height 10 m possess a potential energy of 200 J. What will be the kinetic energy of this body when it hits the ground? (Neglect air resistance)
The kinetic energy of a body of mass 'X' kg is 200 J when it is moving with a velocity of 2 m/s. What will be the value of X?
Important Questions from Work Power Energy
Which of the following is NOT correct regarding friction?
If a pump can raise 200 liters of water through a height of 300 meters in one minute, how much work can it do in one hour?
Which of the following is an example of kinetic energy?
How much kinetic energy does a 160 g cricket ball have when it is thrown at a speed of 22 m/s?
The movement of birds is an example of _______.
