Problem Set in Physics

1. The body of a man whose weight is 690 N contains about 5.2 x 10 3 m3 (5.5 qt) of blood.(a) blood.(a) Find the blood’s weight and (b) express it as a percentage of the body weight.

2. Suppose that the pressure acting on the back of a swimmer’s hand is 1.2 x 105 Pa, a realistic value near the bottom of the diving end of a pool. The surface area of the back of the hand is 8.4 x 10 3 m2. (a) Determine the magnitude of the force that acts on it. (b) Discuss the direction of the force. 3. As you climb a mountain, your ears “pop” because of the changes in atmospheric pressure. In which direction, outward or inward, does your eardrum move (a) as you climb up and (b) as you climb down? 4. A bottle of juice is sealed under partial vacuum, with a lid on which a red dot or “button” is painted. Around the button the following phrase is printed: “Button pops up when seal is broken.” Why does the button remain pushed in when the seal is intact? (a) The pressure inside the bottle is greater than the pressure outside the bottle. (b) The pressure inside the bottle is less than the pressure outside the bottle. (c) There is greater force acting on the interior surface of the seal than acts on the exterior surface.

5. Blood in the arteries is flowing, but as a first approximation, the effects of this flow can beignored and the blood treated as a static fluid. Estimate the amount by which the blood pressure P 2 in the anterior tibial artery at the foot exceeds the blood pressure P 1 in the aorta at the heart when a person is (a) reclining horizontally and (b) standing. The distance between the two arteries is 1.35m. 6. A garden hose has an unobstructed opening with a cross-sectional area of 2.85 x 10 4 m2, from which water fills a bucket in 30.0 s. The volume of the bucket is 8.00 x 10 3 m3 (about two gallons). Find the speed of the water that leaves the hose through (a) the unobstructed opening and (b) an obstructed opening with half as much area. 7. At what temperature the Celsius and the Fahrenheit scales equal? 8. A steel section of the Alaskan pipeline had a length of 65 m and a\temperature of 18 0C when it  was installed. What is its change in length when the temperature drops to a frigid 45 0C?

9. A steel aircraft carrier is 370 m long when moving through the icy North Atlantic at a temperature of 2.0 0C. By how much does the carrier lengthen when it is traveling in the warm Mediterranean Sea at a temperature of 21 0C?                10. Suppose that the steel gas tank in your car is completely filled when the temperature is 17 0C. How many gallons will spill sp ill out of the twenty-gallon tank when the temperature rises to 35 0C?