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Starting from rest, a wheel has constant α=3.0 rad s-2. During a certain 4.0 s interval, it turns through120 rad. How much time did it take to reach that 4.0 s interval?

Important Questions on Rotation

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JEE Main
IMPORTANT
Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 16
A merry-go-round rotates from rest with an angular acceleration of 1.20 rad s-2. How long does it take to rotate through (a) the first 2.00 rev and (b) the next 2.00 rev?
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 17
At t=0, a flywheel has an angular velocity of 4.7 rad s-1, a constant angular acceleration of -0.25 rad s-2 and a reference line at θ0=0. (a) Through what maximum angle (θmax) will the reference line turn in the positive direction? What are the (b) first and (c) second times the reference line will be at θ=12θmax? At what
(d) negative time and (e) positive time will the reference line be at θ=10.5°? (f) Graph θ versus t and indicate your answers.
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 18
A pulsar is a rapidly rotating neutron star that emits a radio beam the way a lighthouse emits a light beam. We receive a radio pulse for each rotation of the star. The period T of rotation is found by measuring the time between pulses. The pulsar in the Crab nebula has a period of rotation of T=0.033 s that is increasing at the rate of 1.26×10-5 s y-1. (a) What is the pulsar's angular acceleration α? (b) If α is constant, how many years from now will the pulsar stop rotating? (c) The pulsar originated in a supernova explosion seen in the year 1054 . Assuming constant α, find the initial T.
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 19
An open jar of water moves in a vertical circle of radius 0.50 m with a frequency that is small enough to put the water on the verge of falling out of the jar at the top of the circle. If the same demonstration were repeated on Mars, where the gravitational acceleration is only 3.7 m s-2, what is the change in the circling frequency to again put the water on the verge of falling out at the top point?
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JEE Main
IMPORTANT
Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 20
An object rotates about a fixed axis, and the angular position of a reference line on the object is given by θ=0.40 e2t, where θ is in radians and t is in seconds. Consider a point on the object that is 6.0 cm from the axis of rotation. At t=0, what are the magnitudes of the point's (a) tangential component of acceleration and (b) radial component of acceleration?
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 21
Between 1911 and 1990, the top of the leaning bell tower at Pisa, Italy moved towards the south at an average rate of 1.2 mm year-1 . The tower is 55 m tall. In radians per second, what is the average angular speed of the towers top about its base?
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 22
Starting from rest at time t=0, a circus stunt man drives a motorbike on a horizontal circular track of radius10.0 m. His speed is given by v=ct2, where, c=1.00 m s-3. At t=2.00 s, what is the angle between his (total) acceleration vector and his radial acceleration vector?
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Principles Of Physics International Student Version>Chapter 10 - Rotation>Problems>Q 23
A flywheel with a diameter of 1.20 m is rotating at an angular speed of 200 rev min-1. (a) What is the angular speed of the flywheel in radians per second?
(b) What is the linear speed of a point on the rim of the flywheel? (c) What constant angular acceleration (in revolutions per minute-squared) will increase the wheel's angular speed to 1000 rev min-1 in  60.0 s? (d) How many revolutions does the wheel make during that 60.0 s?