A penny is placed on a turntable which is spinning clockwise as shown in Fig. 5-37. If the power to the turntable is turned off, which arrow best represents the direction of the acceleration of the penny at point P while the turntable is still spinning but slowing down? OP FIGURE 5–37 MisConceptual Question 12. (a) (b) (c) (d) (e)

Answer detailly 7(iii)

During a very quick stop, a car decelerates at 12 (a) What is the angular acceleration of its 0.27 m radius tires, assuming they do not slip on the pavement? Hint: Don't forget the sign. a = S rad S² (b) How many revolutions do the tires make before coming to rest, given their initial angular velocity rad is 98 -? 3 revolutions (c) How long does the car take to stop completely? t = S

In which of the following situations is the angular acceleration equal to zero? Mark only one. O A fan in the process of slowing from its maximum spin to zero. A ball rolling down a hill A merry-go-round that starts at rest and is pushed by a child until it speeds up O The tire of a car that is traveling at a constant speed in a straight line.

1. For this series of 4 questions, a rider rides in a car that is connected to a 4-m rod, and rotates about the z axis. The rod of negligible mass is subjected to a constant couple moment of M, and the engine of the car supplies a traction force of F. Neglect the size of the car. You will be asked to solve for different things. Please pay attention: the numbers may change from problem to problem since they are randomized. 3) If the rod is subjected to a constant couple moment of M = 800 N•m, and the engine of the car supplies a traction force of F=11•t N to the wheels, where tis in seconds, what is the magnitude of the angular impulse from the moment and the force to the car-rider system in kg•m²/s from t = 0 to t = 5.7 s? Your answer must include 1 place after the decimal point. Your Answer: Answer M 4 m F

Thomas Bradshaw invented the first Merry-Go-Round to be operated by a steam engine. If the engine suddenly stopped, and the Merry Go Round experienced no friction or air resistance, how could the riders on the ride slow its rotational motion? Run toward the edge of the platform. Run toward the center of the platform. Jump off the ride all at once. Lay down flat on the platform.

3. A ball rolls along the smooth frictionsless track shown in in the figure below with an initial speed of 5.00 m/s. Assume that the ball turns all the corners smoothly with no loss of speed. Calculate to three significant figures despite what the figure shows. (a) What is the ball’s speed as it goes over the top? (b)  What is its speed when it reaches the level track on the right side? (c) What is the difference between the final speed and the initial speed?

• A data CD takes 3 [seconds] to reach its operating rotational speed of 5400 [rpm] (revolutions per minute). What is the CD's average acceleration while it is getting up to speed? A) 190 [rad/s²] 1,700 [rad/s²] B) C) 16,200 [rad/s²] D) Don't know Who uses CD's anymore? E)

6) A grindstone (Fig. 10-8) rotates at constant angular acceleration a=0.35 rad/s² . At time 1 = 0, it has an angular velocity of horizontal, at the angular position 0 = 0 = 4.6 rad/sand a reference line on it is We measure rotation by using this reference line. Clockwise negative Counterclockwise = positive Axis -Reference line Zero angular position Figure 10-8 A grindstone. At t=0 the reference line (which we imagine to be marked on the stone) is horizontal. (a) At what time after t=0 is the reference line at the angular position=5.0 rev?