Someone hits a tether ball to make it spin around a pole. The cord that attaches the tether ball to the central pole then winds around the pole. What happens to the angular speed of the tether ball during this process?
1.It decreases.
2.It increases.
3.It remains constant.
4.It cannot be determined.
[Ques. 2] A popular demonstration involves a professor, initially motionless, standing on a low-friction turntable and holding a bicycle wheel that is spinning horizontally. What happens when the professor flips the bicycle wheel so that it is spinning in the other direction?
1.She starts to spin in the same direction as the initial direction of the bicycle wheel.
2.She starts to spin in the bicycle wheel's new spin direction.
3.She remains stationary.
4.It is impossible to tell because it depends on how fast the bicycle wheel initially spins.
[Ques. 3] If global warming were to occur over the next century, it is likely that some polar ice would melt, causing more water to be distributed evenly all over the Earth. What would happen to the length of the day as a result of this?
1.It would increase.
2.It would decrease.
3.Nothing, it would stay the same.
4.It is impossible to tell.
[Ques. 4] A skater rotates quickly on the ice. He pushes his arms out. What happens to his rotational kinetic energy?
1.It increases.
2.It decreases.
3.It stays the same.
4.It is impossible to determine.
[Ques. 5] A skater rotates quickly on the ice. He pushes his arms out. What happens to his angular speed?
1.It increases.
2.It decreases.
3.It stays the same.
4.It is impossible to determine.
[Ques. 6] Consider a solid sphere and a hollow sphere of the same radius, both made of material with the same density. They are both rotating on their axes with the same angular speed. Which one has the higher angular momentum?
1.the solid sphere
2.the hollow sphere
3.They both have the same angular momentum.
4.It is impossible to determine.
[Ques. 7] If you see an object rotating, is there necessarily a net nonzero torque acting on it?
1.yes.
2.only if it is rotating with a constant angular speed
3.No, a net nonzero torque would not cause an object to rotate.
4.only if the object's angular speed changes
[Ques. 8] Complete the following sentence: The moment of inertia of an object
1.depends on the rotational speed of the object.
2.will be greater for a larger-massed object than for a smaller-massed object.
3.is not a function of the object's mass.
4.is a function of the axis about which the object is spun.
[Ques. 9] A ball rolls without slipping down incline A, starting from rest. At the same time, a box starts from rest and slides down incline B, which is identical to incline A except it is frictionless. Which has a larger translational speed at the bottom of the ramp?
1.They have the same translational speed at the bottom of the ramp.
2.the ball
3.the box
4.It is impossible to determine.
[Ques. 10] A rod attached to the shaft of a motor at the center of the rod so that the rod is perpendicular to the shaft, as in figure a. The motor is turned on and performs work W on the rod, accelerating it to an angular speed . The system is brought to rest and the attachment to the rod is then moved along the shaft such that the rod is spun from its end instead, as in figure b. If the controls of the motor are adjusted such that the rod is accelerated from rest to the same angular speed of in this new configuration, how much work does the motor do on the rod in this case?
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