QUIZ 2

In reality, this actually is the quiz I had planned to give last Thursday, subject to technical errors and a rethinking of the best strategy leading to your success. With this gift, always remember these best kept words: A sample quiz is only a guide not a guarantee for your success next Tuesday, last part of period. For example there will be questions derived from the home problems on the previous page.

QUIZ 8

1. As the altitude increases, the density of air in the atmosphere
(a) increases (b) decreases (c) remains the same (d) nota

2. When an air bubble rises in water, its volume
(a) decreases ( (b) increases (c) remains the same (d) nota

3. You are on an airplane at high altitude going to New York and you are holding an un-opened air tight bag of organic, non GMO corn chips. When you land you notice the bag of chips is

(a) more puffed up (b) less puffed up (c) the same because the chips are organic (d) nota

4. As discussed on the homework, assume you are boarding an airplane and you are holding an un-opened air tight bag of black bean chips. When you are in flight you notice the bag of chips is

(a) the same because the chips are not organic (b) more puffed up (c) less puffed up (d) nota

5. In the previous problem, the bag changes size because the atmospheric pressure in the airplane
(a) increases (b) is the same if the chips are not organic
(c) decreases (d) nota

6. If a liquid twice as dense as mercury were used in a barometer, how high would the level be on a day of normal atmospheric pressure?
(a) 380 mm (b) 760 mm (c) 190 mm (d) nota

7. Which is larger, the buoyant force on a large elephant or on a helium-filled balloon of exactly the same volume ?
(a) buoyant force on elephant (b) buoyant force on balloon (c) same buoyant force

8. Which is larger, the buoyant force on a large elephant or on a small birthday party helium-filled balloon ?
(a) buoyant force on elephant (b) buoyant force on balloon (c) same buoyant force

9. Which weighs more, a bottle of helium gas or an identical bottle of air? Assume the density of helium is less than that of air.

(a) Helium (b) Air

10. In the previous problem, which bottle experiences the larger buoyant force?
(a) helium bottle (b) air bottle (c) both experience the same buoyant force.

11. The force of the outside atmosphere at sea level against a 10 m² glass window is about a million N, pointing to the left. Why does the window not shatter?

(a) Because the window is probably tinted and absorbs some of the outside light (b) Because the force of the inside air and mechanical l forces cancel the leftward force. (c) nota

12. What is the water pressure 20 m below the surface of a lake of water? The density of water is 1000 kg/m³ . For this problem's computation, you may assume that g = 10 m/s². Be careful with your units.

a. 100000 N/m²

b. 100000 N

c. 200000 N

d. 200000 N/m²

e. nota

13. In Hooke's Law, the magnitude of the force needed to stretch a spring a distance D is
(a) k*D (b) (1/2)*k*D²

14. A satellite moves in a circular orbit around a planet. During its motion its kinetic energy
(a) changes continuously (b) remains the same (c) nota

FORMULA PROBLEMS BELOW

15. True or False. In Chapter 14, the buoyant force is defined as the weight of the air displaced by the object.
(a) True (b) False

16. The formula for water pressure at a depth h below the surface is
(a) (mass density of water)*g *h (b) (mass density of water)*h (c) nota

17. We defined mass density of an object as (a) mass /volume (b) mass/(surface area) (c) nota

18. What are the units of pressure?
(a) N/m² (b) N (c) nota