An electric fan rotating with 3revs-1 is switched off. It comes to rest in 2sec having a constant deceleration of 1revs-2. How many revolutions did it turn before coming to rest?
Correct answer: B. 8 revolutions
- A. 6 revolutions
- B. 8 revolutions
- C. 2 revolutions
- D. 10 revolutions
Explanation
θ = ωit + -2αt2 = (3)(2) + 1/2(1)(2)2= 6+ 2= 8 rev
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About Simple Harmonic Motion
Simple harmonic motion is oscillation in which acceleration is directly proportional to displacement and directed toward the equilibrium position. Work includes displacement, velocity, acceleration, phase, period, frequency, amplitude and energy, with applications to springs and simple pendulums. The restoring force and the conditions for SHM distinguish it from general periodic motion.
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