Question 1 1 points Save A body’s center of…


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25.50

Question 1 1 points Save A body’s center of gravity . . . is always in the middle of an object. is the point about which a body’s own weight exerts no net torque on the body itself. depends on the value of acceleration due to gravity. depends on the weight of the object. Question 2 1 points Save Evaluate the statement: Torque is the rotational counterpart of force. The statement is true because they have the same units. The statement is false because they do not have the same units. The statement is true because both may cause a change in a body’s motion. The statement is false because force acts either in the direction of motion or against it, while torque acts at right angles to motion. Question 3 1 points Save What is meant by the term moment of inertia (also referred to as rotational inertia)? It refers to how long it takes before an object begins spinning after the application of a torque. It refers to a body’s resistance to horizontal motion. It refers to a body’s resistance to a change in vertical motion. It refers to a body’s resistance to a change in rotational motion. Question 4 1 points Save Consider a diver who wishes to complete a double back tuck dive. In this dive, he leaves the board, pulls his legs up to his chest, completes 2 revolutions, and straightens his body before entering the water. When does the diver have the largest rotational velocity? Immediately after leaving the board. When his legs are pulled up to his chest. When he is stretched out just before entering the water. His angular velocity is virtually constant throughout the dive. Question 5 1 points Save Consider a meter stick with a pivot point in the center. A force of 1 N is placed on one end of a meter stick. Where would a weight of 3 N need to be placed for the meter stick to balance? At the other end opposite the 1 N weight. 1/3 the way to the end opposite the 1 N weight. 1/2 way to the end opposite the 1 N weight. Impossible to tell with the given information. Question 6 1 points Save Consider two objects of equal mass and radius: a hollow ball and a solid ball. Which has the largest moment of inertia? The hollow ball. The solid ball. The moments of inertia of the objects are the same. Question 7 1 points Save Suppose you are with group riding on a merry-go-round at a playground. If everyone suddenly piles into the center, the ride speeds up. Why? The terminal velocity increases. The friction decreases. Piling into the center exerts a torque on the system. The rotational inertia decreases. Question 8 1 points Save Why is it easier to hold a dumbbell close to your body than it is to hold it at arm’s length? The inertia of the dumbbell is greater at arm’s length. The torque on your arm is greater at arm’s length. The force is greater at arm’s length. The angle is greater at arm’s length. Question 9 1 points Save A 20 N force is applied to the outer bottom rim of a wheel of radius 0.75 m to the right. A 50 N force is applied to the left side of the inner edge of the wheel (radius = 0.5 m) in the upward direction. What is the net torque on the wheel? -10 Nm (clockwise). +10 Nm (counterclockwise) – 35 Nm (clockwise) + 35 Nm (counterclockwise) Question 10 1 points Save If a Ferris Wheel takes 2 minutes to go from rest to a rotational velocity of 1 revolution per minute, what is its rotational acceleration? 1 rev/min/min 1/2 rev/min/min 2 rev/sec/sec 2 rev/min/min

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25.50