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Which object or objects below have angular momentum?
a spinning top correct
a car speeding down a straight road correct
the earth correct
a car racing around an oval track
You are collecting data to study changes in the angular momentum of a bicycle wheel when a force is applied to it. Which of the following measurements would be least helpful to you?
the angular velocity of the wheel when the force is applied
Why is it important to consider the shape of an object when determining the object's angular momentum?
The shape determines the location of the center of mass. The location of the center of mass contributes to the object's rotational inertia, which contributes to its angular momentum.
If angular momentum is pointing straight down, what is the direction of the corresponding rotation, when viewed from above?
Clockwise correct
What is the angular momentum of the Moon in its orbit around Earth in m2/s? (treat the moon as a point mass)
2.89E34
First, find the values for the orbit of the moon. Mass=7.35×1022kg, radius of orbit=3.84×108m, period of rotation is 27.3days, which converts to an angular velocity of 2.66×10−6rad/s. Then use L=Iω, where I =mr2.
Consider a system like the example problem where a batting machine swings a bat but instead of a baseball, the bat hits a lump of clay, which sticks to the end of the bat. The tip of the bat has a velocity of 10m/s and the clay approaches at 5m/s. How does the angular momentum of the clay and bat after the collision compare to the angular momentum of the clay and bat before the collision, and why?
It stays the same, there is no external torque on the system
A lever is placed on a fulcrum. A rock is placed on the left end of the lever and a downward (clockwise) force is applied to the right end of the lever. What measurements would be most effective to help you determine the angular momentum of the system? (Assume the lever itself has negligible mass.)
the mass of the rock, the length of the lever on both sides of the fulcrum, and the force applied on the right side of the lever
What torque applied to a disk with radius 7.0cm for 3.5s will produce an angular momentum of 25Nms?
7.14
Suppose a child walks from the outer edge of a rotating merry-go round in towards the center of rotation. Does the angular velocity of the merry-go-round increase, decrease, or remain the same?
increases
What quantity determines whether or not angular momentum is conserved in a collision?
A net external torque.
Why doesn't a rapidly spinning toy gyroscope fall over?
The net external torque is horizontal and in a direction perpendicular to the angular momentum.
