In which of the following case(s) the work done be positive?
Correct answer: A. Object moves in the direction of Force
- A. Object moves in the direction of Force
- B. Object moves in opposite direction of Force
- C. Object moves at Right Angle to the Force
- D. Both a and c
Explanation
Work done by a force is defined as the product of the force and the displacement of the object in the direction of the force. Mathematically, it is given by:CopyW = F.d = Fd cosθwhere:W is the work doneF is the forced is the displacementθ is the angle between the force and displacementWhen the object moves in the direction of the force, the angle between the force and displacement is 0 degrees. Therefore, cosθ = 1 and the work done is positive.When the object moves in the opposite direction of the force, the angle between the force and displacement is 180 degrees. Therefore, cosθ = -1 and the work done is negative.When the object moves at a right angle to the force, the angle between the force and displacement is 90 degrees. Therefore, cosθ = 0 and the work done is zero
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About Work and Energy
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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