Water help: Need help with some physics questions. - Help.com

Need help with some physics questions.

please help!!answer any that look easy to you.

1. A water pool is 30 m deep. The density of water is 1000 kg/m 3.
What is the pressure at the base of the pool?
Neglect the pressure due to atmosphere and the acceleration of gravity is 9.8 m/s 2.
Answer in units of N/m 2 .

2.  Do light objects tend to sink or float? Can something similar be concluded about heavy objects?
a. All light objects float.
b. Weight is not the critical factor; it also depends on volume.
c. Most heavy objects sink.
d. There is a critical mass for each material that determines whether or not it will float.

3. At what level (vertically) should you hold a cut finger to reduce bleeding?
a. at the same level as your heart
b. as far from your heart as possible at any level
c. as high as possible
d. as low as possible

4. Assume you are floating in water with your lungs full of air. When you exhale, you sink lower in the water.What is a possible explanation of the sinking effect?
I) Your volume decreases and so does the buoyant force.
II) Your mass decreases as you let the air out of your lungs making it easier for you to sink.
III) Your overall densitydecreases.
IV) Your overall densityincreases.
a. I and II only
b. I only
c. III only
d. IV only
e. II only
f. II and III only
g. I, II, and III only
h. II and IV only
i. I and III only
j. I and IV only

5. A piece of iron is sitting on a block of wood floatingin water. If the iron were instead suspended beneath the wood, would the wood float at the same level, lower, or higher?
a. It depends on the ratio of iron and wood volumes.
b. Higher, because there is a buoyant force acting on the iron now.
c. Definitelylower, because the iron is under the wood.
d. It would float at the same level.
e. It would float only slightlylower, because the iron displaces a little water andthe overall water level rises.

6. Do the stones hurt your feet less or more in the water than on the stonybeach? Explain.
a. The stones hurt more in the water;the buoyant force increases as we go deeper.
b. As you enter the water they hurt more at first and then less; until we start floating we “sink” onto the stones, but once we start
floating the displaced water lifts us up.
c. It feels exactlythe same;our mass doesn’t change, so we press down on our feet in the same way.
d. The stones hurt less in the water; the buoyant force lifts us up.

7. A block of aluminum with a volume of 8.5 cm 3 is placed in a beaker of water filled to the brim and sinks. Water overflows. The same happens in another beaker with a 8.5 cm 3 block of lead. The lead willdispla(more, less, the same amount of) water than the aluminum block does.
a. less
b. the same
c. more
d. It cannot be determined without a direct measurement.

8. A block of aluminum with a mass of 7 kg is placed in a beaker of water filled to the brim and sinks. Water overflows. The same happens in another beaker with a 7 kg block of lead. The lead willdisplace (more, less, the same amount of) water than the aluminum block does.
a. less
b. more
c. It cannot be determined without a direct measurement.
d. the same

9. If liquid pressure were the same at all depths, would there be a buoyant force on an object submerged in the liquid?
a. Yes;directed down
b. Yes;but it will be very small.
c. No; buoyant force is the result of differ-ences in pressure.
d. Yes;it is determined by the volume ofthe submerged object.
e. Yes;it pushes an object out of liquid.

10. Why does a can of diet drink float in water, while a can of regular soda sinks?
a. Diet soda is less dense than a regular soda.
b. Regular soda has fewer gas bubbles.
c. Diet soda cans are slightly smaller.
d. It depends on the brand and the actual ingredients.
e. Sugar is heavier than a sugar substitute.

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