If a variable force F = 2x is applied, what will be the work done in moving the particle from X= 10 to 0?
Correct answer: D. -100J
- A. 100J
- B. 50J
- C. -50J
- D. -100J
Explanation
At the initial position, x = 10, force f = 20. At the final position, x = 0, and f = 0. Because the force varies linearly with position x, the average force is (20+0)/2 = 10. Work is the product of force and displacement (change of position). The displacement from 10 to 0 is 0 -10 = -10, so work W = (average force) * (displacement) = 10*10 = -100. It is negative because the displacement was in the opposite direction of the force. The source of the force took energy from the particle.
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About Work
Work is done when a force produces displacement, with its value determined by the component of force along the displacement. The topic covers positive, negative and zero work, work by variable forces from force-displacement graphs, and the connection between net work and change in kinetic energy.
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