FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 7: Rotational Motion

Show Answer

Share

---

All types

Filters

Study FlashcardsPractice ExamLearn

Question 31

Short Answer

Review LaterAdd Note

Review Later

A bicycle wheel has an initial angular speed of 7.2 rad/s. After turning through $\text { one-half }$ of a revolution, the angular speed is reduced to 2.2 rad/s. If the angular acceleration of the wheel was constant during the motion, how long will it take the wheel to make the $\text { one-half }$ revolution?

Correct Answer

verified

Show Answer

Question 32

Multiple Choice

Review LaterAdd Note

Review Later

Two forces produce equal torques on a door about the door hinge. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force has a greater magnitude?

A) the first force (at the midpoint)
B) the second force (at the doorknob)
C) The two forces are equal.

Correct Answer

verified

Show Answer

Question 33

Multiple Choice

Review LaterAdd Note

A wheel rotates through an angle of 13.8 rad as it slows down uniformly from 22.0 rad/s to 13.5 rad/s. What is the magnitude of the angular acceleration of the wheel?

A wheel of diameter 0.70 m rolls on the floor without slipping. A point at the top of the wheel moves with a speed 2.0 m/s relative to the floor. (a)At what speed is the central axis of the wheel moving relative to the floor? (b)What is the angular speed of the wheel?

When a fan is turned off, its angular speed decreases from 10 rad/s to 6.3 rad/s in 5.0 s. What is the magnitude of the average angular acceleration of the fan?

A 1.53-kg bucket hangs on a rope wrapped around a pulley of mass 7.07 kg and radius 66 cm. This pulley is frictionless in its axle, and has the shape of a solid uniform disk. After the bucket has been released, (a)what is the angular acceleration of the pulley, and (b)what is the acceleration of the bucket?

An old LP record that is originally rotating at 33.3 rad/s is given a uniform angular acceleration of 2.15 rad/s². Through what angle has the record turned when its angular speed reaches 72.0 rad/s?

A force of $16.88 \mathrm {~N}$ is applied tangentially to a wheel of radius 0.340 m and causes an angular acceleration of 1.20 rad/s². What is the moment of inertia of the wheel?

A machinist turns on the power on to a grinding wheel at time t = 0 s. The wheel accelerates uniformly from rest for 10 s and reaches the operating angular speed of $96 \mathrm { rad } / \mathrm { s }$ The wheel is run at that angular velocity for 40 s and then power is shut off. The wheel slows down uniformly at $1.5 \mathrm { rad } / \mathrm { s } ^ { 2 }$ until the wheel stops. For how long a time after the power is shut off does it take the wheel to stop?

A wheel starts from rest and has a uniform angular acceleration of 4.0 rad/s². After the wheel completes its first revolution, how long does it take for it to make its second complete revolution?

A mechanic is examining the wheel of a bicycle to adjust the brake. With the bicycle off the ground, he manually rotates the wheel until it reaches an angular speed of 12.0 rad/s and then allows it to coast to a stop. If the wheel has a moment of inertia of 0.100 kg ∙ m², and the wheel slows uniformly to a stop in 160 s, what is the magnitude of the retarding torque?

A child is riding a merry-go-round that has an instantaneous angular speed of 1.25 rad/s and an angular acceleration of 0.745 rad/s². The child is standing 4.65 m from the center of the merry-go-round. What is the magnitude of the linear acceleration of the child?

The center of mass (or center of gravity) of a two-particle system is at the origin. One particle is located at (3.0 m, 0.0 m) and has a mass of 2.0 kg. The other particle has a mass of 3.0 kg. What is the location of the 3.0-kg particle?

How long does it take for a rotating object to speed up from 15.0 rad/s to 33.3 rad/s if it has a uniform angular acceleration of 3.45 rad/s²?

Through how many degrees does a 33 rpm turntable rotate in $0.32 \mathrm {~s} ?$

As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?

What is the angular speed, in rad/s, of a flywheel turning at 813.0 rpm?

A 1.0-g bead is at (-2.0 cm, 2.0 cm), a 2.0-g bead is at (2.0 cm, -4.0 cm), and a 3.0-g bead is at (2.0 cm, 0.0 cm). What are the coordinates of the center of mass (or center of gravity)of this system of beads?

In the figure, a weightlifter's barbell consists of two identical small but dense spherical weights, each of mass 50 kg. These weights are connected by a thin 0.96-m rod with a mass of 24 kg. Find the moment of inertia of the barbell through the axis perpendicular to the rod at its center, assuming the two weights are small enough to be treated as point masses.

A rolling wheel of diameter of 68 cm slows down uniformly from 8.4 m/s to rest over a distance of 115 m. What is the magnitude of its angular acceleration if there was no slipping?