A sled moves on essentially frictionless ice It
- Slides: 6
A sled moves on essentially frictionless ice. It is attached by a rope to a vertical post set in the ice. Once given a push, the sled moves around the post at constant speed in a circle of radius R. If the rope breaks, A. the sled will keep moving in a circle. B. the sled will move on a curved path, but not a circle. C. the sled will follow a curved path for a while, then move in a straight line. D. the sled will move in a straight line. © 2012 Pearson Education, Inc.
Q 5. 12 A pendulum bob of mass m is attached to the ceiling by a thin wire of length L. The bob moves at constant speed in a horizontal circle of radius R, with the wire making a constant angle with the vertical. The tension in the wire A. is greater than mg. B. is equal to mg. C. is less than mg. D. is any of the above, depending on the bob’s speed v. © 2012 Pearson Education, Inc.
Q 5. 13 A pendulum of length L with a bob of mass m swings back and forth. At the low point of its motion (point Q ), the tension in the string is (3/2)mg. What is the speed of the bob at this point? P R Q © 2012 Pearson Education, Inc.
A small ball is released from rest at position A and rolls down a vertical circular track under the influence of gravity. When the ball reaches position B, which of the indicated directions most nearly corresponds to the direction of the normal force on the ball? Enter (9) if the direction cannot be determined. 1. 2. 3. 4. 5. 6. 7. 8. 9. 1 2 3 4 5 6 7 8 9 © 2012 Pearson Education, Inc.
A child is practicing for a BMX race. His speed remains constant as he goes counterclockwise around a level track with two straight sections and two nearly semicircular sections as shown in the aerial view of Figure OQ 6. 3. Rank the magnitudes of his acceleration at the points A, B, C, D, and E from largest to smallest. If his acceleration is the same size at two points, display that fact in your ranking. If his acceleration is zero, display that fact. 1. 2. 3. 4. B>D=E>A>C=0 A>C=D>B=E=0 C>D>E>A=B=0 A=C=D>B>E=0 © 2012 Pearson Education, Inc.
A child is practicing for a BMX race. His speed remains constant as he goes counterclockwise around a level track with two straight sections and two nearly semicircular sections as shown in the aerial view of Figure OQ 6. 3. What are the directions of his velocity at points A, B, and C? For each point, choose one: north, south, east, west, or nonexistent. 1. 2. 3. 4. © 2012 Pearson Education, Inc. north at A, west at B, and south at C south at A, east at B, and north at C nonexistent at A, west at B, and south at C west at A, nonexistent at B, and east at C.
