Phy 101 week 2 individual assignment textbook exercise
36. As you stand on a floor, does the floor exert an upward force against your feet? How much force does it exert? Why are you not moved upward by this force?
39. In order to slide a heavy cabinet across the floor at constant speed, you exert a horizontal force of 600 N. Is the force of friction between the cabinet and the floor greater than, less than, or equal to 600 N?
47. The smokestack of a stationary toy train consists of a vertical spring gun that shoots a steel ball a meter or so straight into the air—so straight that the ball always falls back into the smokestack. Suppose the train moves at constant speed along the straight track. Do you think the ball will still return to the smokestack if shot from the moving train? What if the train gains speed along the straight track? What if it moves at a constant speed on a circular track? Why do your answers differ?
Chapter 11: 1, 3 & 10
1. How many types of atoms can you expect to find in a pure sample of any element?
3. When a container of gas is heated, what happens to the average speed of its molecules?
10. Your friend says that what makes one element distinct from another is the number of electrons about the atomic nucleus. Do you agree wholeheartedly, partially, or not at all?
Chapter 12: 2
2. Your friend says that the primary difference between a solid and a liquid is the kind of atoms in the material. Do you agree or disagree, and why?
Chapter 13: 3 & 57
3. Which is more likely to hurt—being stepped on by a 200-lb man wearing loafers or being stepped on by a 100-lb woman wearing high heels?
57. In the hydraulic arrangement shown in Figure 13.22, the multiplication of force is equal to the ratio of the areas of the large and small pistons. Some people are surprised to learn that the area of the liquid surface in the reservoir of the arrangement shown in Figure 13.23 is immaterial. What is your explanation to resolve this confusion?
Chapter 14: 12, 25 & 28
12. Why do you suppose that airplane windows are smaller than bus windows?
25. Why is it so difficult to breathe when snorkeling at a depth of 1 m and practically impossible at a 2-m depth? Why can’t a diver simply breathe through a hose that extends to the surface?
28. Why does the weight of an object in air differ from its weight in a vacuum (remembering that weight is the force exerted against a supporting surface)? Cite an example in which this would be an important consideration
Preview of solution:
Chapter 6: Momentum (Questions 8, 20, 58, and 60)
8.) When a person falling feet-first hits concrete, they stop falling immediately; when a person hits soil, they almost stop immediately but the soil has a little give; and when a person hits water, the person is gradually slowed down by the water but not immediately stopped. The ability to survive the impact of a feet-first fall depends on the type of surface that the person hits. A surface that immediately stops the falling person allows no give, permitting for a slower speed value in surviving the fall. A surface that gradually slows down the falling person allows a give, permitting for a faster speed value in surviving the fall.
20.) A baseball catcher’s mitt has more padding because the catcher is constantly catching a baseball that is being thrown by the pitcher at excessive speeds over and over. In order to cushion the constant impacts of the baseball being thrown, the catcher’s mitt must have a larger amount of padding than a conventional glove.
58.) In order for the billiard ball to fully come to a stop on impact, the ball must transmit all of its kinetic angular momentum to the ball at rest. Since a billiard ball traveling at an angle is not capable to transmit all of its kinetic energy to the ball at rest, it is incapable to wholly come to a stop on impact.
60.) I agree with the first friend saying that it is related to the negative momentum of the golf ball after the collision with the bowling ball, because of the Law of Conservation of Momentum. Since the initial momentum of the golf ball was in one direction, moving in the reverse direction after impact acquires negative momentum with recognition to the bowling ball’s momentum. To counterbalance the negative momentum, the bowling ball’s momentum must be larger than the initial momentum of the golf ball.
Chapter 7: Energy (Questions 14, 36, 42, 56, and 57)
14.) When flexible fiberglass poles were first inserted into the sport of pole vaulting, it forced pole vaulters to alter their form to best fit the elastic potential energy of the new poles in comparison to the non-flexible stiff wooden pools that were previously used.
36.) Work is force multiplied by distance. The decreased force is compensated by a larger distance, therefore, the lever of the jack has to be shifted upward and downward numerous times.
42.) The terminal speed of both balls is the same whether it was thrown downward or upward from the rooftop. Once terminal speed is attained, falling a further distance does not affect the speed of either ball.
56.) Momentum would be conserved if a single ball popped out with twice the initial speed. Since kinetic energy equals 1/2mv², this circumstance would cause .0.the final kinetic energy twice as much as the initial kinetic energy. For that reason, this does not happen.
57.) No. Energy is never lost. By wasting energy, the machine is not as proficient at converting input into work as it could be. Normally, the energy is converted into friction or heat and is considered as a loss, although, the total amount of energy is equal.
Preview of solution:
Chapter 6: Momentum (Questions 8, 20, 58, and 60)
8.) When a person falling feet-first hits concrete, they stop falling immediately; when a person hits soil, they almost stop immediately but the soil has a little give; and when a person hits water, the person is gradually slowed down by the water but not immediately stopped. The ability to survive the impact of a feet-first fall depends on the type of surface that the person hits. A surface that immediately stops the falling person allows no give, permitting for a slower speed value in surviving the fall. A surface that gradually slows down the falling person allows a give, permitting for a faster speed value in surviving the fall.
20.) A baseball catcher’s mitt has more padding because the catcher is constantly catching a baseball that is being thrown by the pitcher at excessive speeds over and over. In order to cushion the constant impacts of the baseball being thrown, the catcher’s mitt must have a larger amount of padding than a conventional glove.
58.) In order for the billiard ball to fully come to a stop on impact, the ball must transmit all of its kinetic angular momentum to the ball at rest. Since a billiard ball traveling at an angle is not capable to transmit all of its kinetic energy to the ball at rest, it is incapable to wholly come to a stop on impact.
60.) I agree with the first friend saying that it is related to the negative momentum of the golf ball after the collision with the bowling ball, because of the Law of Conservation of Momentum. Since the initial momentum of the golf ball was in one direction, moving in the reverse direction after impact acquires negative momentum with recognition to the bowling ball’s momentum. To counterbalance the negative momentum, the bowling ball’s momentum must be larger than the initial momentum of the golf ball.
Chapter 7: Energy (Questions 14, 36, 42, 56, and 57)
14.) When flexible fiberglass poles were first inserted into the sport of pole vaulting, it forced pole vaulters to alter their form to best fit the elastic potential energy of the new poles in comparison to the non-flexible stiff wooden pools that were previously used.
36.) Work is force multiplied by distance. The decreased force is compensated by a larger distance, therefore, the lever of the jack has to be shifted upward and downward numerous times.
42.) The terminal speed of both balls is the same whether it was thrown downward or upward from the rooftop. Once terminal speed is attained, falling a further distance does not affect the speed of either ball.
56.) Momentum would be conserved if a single ball popped out with twice the initial speed. Since kinetic energy equals 1/2mv², this circumstance would cause .0.the final kinetic energy twice as much as the initial kinetic energy. For that reason, this does not happen.
57.) No. Energy is never lost. By wasting energy, the machine is not as proficient at converting input into work as it could be. Normally, the energy is converted into friction or heat and is considered as a loss, although, the total amount of energy is equal.
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