Mechanics Questions 3, Fall 2017 Please read carefully and answer properly Question Title * 1. Your Name: Question Title The questions immediately below refer to a large truck which breaks down out on the road and receives a push back to town by a small compact car. Question Title Pick one of the choices A through J below which correctly describes the forces between the car and the truck for each of the descriptions. Question Title * 2. The car is pushing on the truck, but not hard enough to make the truck move. A B C D E J Question Title * 3. The car, still pushing the truck, is speeding up to get to cruising speed. A B C D E J Question Title * 4. Two metal balls are the same size but one weighs twice as much as the other. The balls are dropped from the roof of a single story building at the same instant of time. The time it takes the balls to reach the ground below will be: about half as long for the heavier ball as for the lighter one. about half as long for the lighter ball as for the heavier one. about the same for both balls. considerably less for the heavier ball, but not necessarily half as long. considerably less for the lighter ball, but not necessarily half as long Question Title * 5. In this situation: two metal balls of the previous problem roll off a horizontal table with the same speed. both balls hit the floor at approximately the same horizontal distance from the base of the table. the heavier ball hits the floor at about half the horizontal distance from the base of the table than does the lighter ball. the lighter ball hits the floor at about half the horizontal distance from the base of the table than does the heavier ball. the heavier ball hits the floor considerably closer to the base of the table than the lighter ball, but not necessarily at half the horizontal distance. the lighter ball hits the floor considerably closer to the base of the table than the heavier ball, but not necessarily at half the horizontal distance. Question Title USE THE STATEMENT AND FIGURE BELOW TO ANSWER THE NEXT TWO QUESTIONS. The accompanying figure shows a frictionless channel in the shape of a segment of a circle with center at "O". The channel has been anchored to a frictionless horizontal table top. You are looking down at the table. Forces exerted by the air are negligible. A ball is shot at high speed into the channel at "p" and exits at "r." Question Title * 6. Consider the following distinct forces: 1. A downward force of gravity. 2. A force exerted by the channel pointing from q to O. 3. A force in the direction of motion. 4. A force pointing from O to q. Which of the above forces is (are) acting on the ball when it is within the frictionless channel at position "q"? 1 only. 1 and 2. 1 and 3. 1, 2, and 3. 1, 3, and 4. Question Title Question Title * 7. Which path in the figure above would the ball most closely follow after it exits the channel at "r" and moves across the frictionless table top? A B C D E Question Title USE THE STATEMENT AND FIGURE BELOW TO ANSWER THE NEXT FOUR QUESTIONSThe figure depicts a hockey puck sliding with constant speed vo in a straight line from point "a" to point "b" on a frictionless horizontal surface. Forces exerted by the air are negligible. You are looking down on the puck. When the puck reaches point "b," it receives a swift horizontal kick in the direction of the heavy print arrow. Had the puck been at rest at point "b," then the kick would have set the puck in horizontal motion with a speed vk in the direction of the kick. Question Title * 8. Which of the paths below would the puck most closely follow after receiving the kick? A B C D E Question Title Question Title * 9. The speed of the puck just after it receives the kick is: equal to the speed "vo" it had before it received the kick. equal to the speed "vk" resulting from the kick and independent of the speed "vo". equal to the arithmetic sum of the speeds "vo" and "vk". smaller than either of the speeds "vo" or "vk". greater than either of the speeds "vo" or "vk", but less than the arithmetic sum of these two speeds. Question Title * 10. Along the frictionless path you have chosen above, the speed of the puck after receiving the kick: is constant. continuously increases. continuously decreases. increases for a while and decreases thereafter. is constant for a while and decreases thereafter. Question Title * 11. Along the frictionless path you have chosen above, the main force(s) acting on the puck after receiving the kick is (are): a downward force of gravity. a downward force of gravity, and a horizontal force in the direction of motion. a downward force of gravity, an upward force exerted by the surface, and a horizontal force in the direction of motion. a downward force of gravity and an upward force exerted by the surface. none. (No forces act on the puck.) Done