Q: A person weighing $$600\ \text{N}$$ stands on one foot with an area of $$0.02\ \text{m}^2. $$What is the pressure exerted on the ground?

$$3.0 \times 10^4$\ \text{Pa}$$

Q: A diver is $$20\ \text{m}$$ below the surface of a lake. What is the absolute pressure at this depth? (Assume $$\rho_{water} = 1000\ \text{kg/m}^3$$, $$g = 9.8\ \text{m/s}^2$$, $$P_{atm} = 1.01 \times 10^5$\ \text{Pa})$$

$$2.97 \times 10^5$\ \text{Pa}$$

Q: If you step on a nail with a heel (area $$1.0 \times 10$$^{-4}$$\ \text{m}^2) $$and your weight is $$500\ \text{N}$$, what pressure is exerted on the nail?

$$5.0 \times 10^6$\ \text{Pa}$$

Q: A water tank is open to the atmosphere and has a depth of $$5\ \text{m}. $$What is the gauge pressure at the bottom of the tank? ($$\rho_{water} = 1000\ \text{kg/m}^3$$, $$g = 9.8\ \text{m/s}^2)$$

$$4.9 \times 10^4$\ \text{Pa}$$

Question 1

A flute is modeled as a tube open at both ends. If the length of the flute is doubled, what happens to the fundamental frequency produced by the flute?

Accepted Answer

It is halved.

Question 2

A tube closed at one end and open at the other produces a fundamental frequency. Which of the following correctly gives the wavelength of this fundamental mode?

Accepted Answer

$$\$$lambda_1$$ = 4L$$

Question 3

Two tuning forks produce frequencies of $$256\ 	ext{Hz}$$ and $$260\ 	ext{Hz}. $$What is the beat frequency heard when both are played together?

Accepted Answer

$$4\ 	ext{Hz}$$

Question 4

A person weighing $$600\ 	ext{N}$$ stands on one foot with an area of $$0.02\ 	ext{m}^2. $$What is the pressure exerted on the ground?

Accepted Answer

$$3.0 	imes 10^4$\ 	ext{Pa}$$

Question 5

A block of wood floats in water with $$60\% of $$its volume submerged. If the density of water is $$1000\ 	ext{kg/m}^3$$, what is the density of the wood?

Accepted Answer

$$600\ 	ext{kg/m}^3$$

Question 6

A hydraulic lift has a small piston of area $$0.01\ 	ext{m}^2$$ and a large piston of area $$1.0\ 	ext{m}^2. If a $$force of $$100\ 	ext{N} is $$applied to the small piston, what is the maximum weight that can be lifted by the large piston (ignoring friction)?

Accepted Answer

$$10,000\ 	ext{N}$$

Question 7

A diver is $$20\ 	ext{m}$$ below the surface of a lake. What is the absolute pressure at this depth? (Assume $$ho_{water} = 1000\ 	ext{kg/m}^3$$, $$g = 9.8\ 	ext{m/s}^2$$, $$P_{atm} = 1.01 	imes 10^5$\ 	ext{Pa})$$

Accepted Answer

$$2.97 	imes 10^5$\ 	ext{Pa}$$

Question 8

A garden hose with a cross-sectional area of $$2.0 	imes 10$$^{-3}$$\ 	ext{m}^2$$ carries water at $$0.5\ 	ext{m/s}. If $$the nozzle at the end has an area of $$5.0 	imes 10$$^{-4}$$\ 	ext{m}^2$$, what is the speed of water as it exits the nozzle?

Accepted Answer

$$2.0\ 	ext{m/s}$$

Question 9

Which of the following best explains why airplane wings generate lift according to Bernoulli’s Principle?

Accepted Answer

Air moves faster over the top of the wing, creating lower pressure above than below.

Question 10

A cube of side $$0.1\ 	ext{m} is $$completely submerged in water. What is the magnitude of the buoyant force acting on the cube? ($$ho_{water} = 1000\ 	ext{kg/m}^3$$, $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$9.8\ 	ext{N}$$

Question 11

A submarine descends from the surface to a depth where the pressure is $$4.01 	imes 10^5$\ 	ext{Pa}. If $$atmospheric pressure is $$1.01 	imes 10^5$\ 	ext{Pa}$$ and $$ho_{water} = 1000\ 	ext{kg/m}^3$$, what is the depth of the submarine?

Accepted Answer

$$30\ 	ext{m}$$

Question 12

A pipe carries water from a reservoir at height $$h_1 to a $$lower point at height $$h_2$$ where the pipe narrows. If the speed of water at the top is $$v_1$$ and at the bottom is $$v_2$$, which of the following is true according to Bernoulli’s equation?

Accepted Answer

$$P_1$$ + \rho g $$h_1$$ + \frac{1}{2}\rho $$v_1^2$$ = $$P_2$$ + \rho g $$h_2$$ + \frac{1}{2}\rho $$v_2^2$

Question 13

A block of mass $$2\ 	ext{kg}$$ and volume $$0.002\ 	ext{m}^3 is $$fully submerged in oil ($$ho_{oil} = 800\ 	ext{kg/m}^3). $$What is the net force acting on the block? ($$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$0.32\ 	ext{N}$$ downward

Question 14

If you step on a nail with a heel (area $$1.0 	imes 10$$^{-4}$$\ 	ext{m}^2) $$and your weight is $$500\ 	ext{N}$$, what pressure is exerted on the nail?

Accepted Answer

$$5.0 	imes 10^6$\ 	ext{Pa}$$

Question 15

A hospital uses a hydraulic lift to raise a patient. If the input piston has an area of $$0.005\ 	ext{m}^2$$ and the output piston has an area of $$0.2\ 	ext{m}^2$$, what input force is needed to lift a $$1000\ 	ext{N}$$ patient?

Accepted Answer

$$25\ 	ext{N}$$

Question 16

A water tank is open to the atmosphere and has a depth of $$5\ 	ext{m}. $$What is the gauge pressure at the bottom of the tank? ($$ho_{water} = 1000\ 	ext{kg/m}^3$$, $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$4.9 	imes 10^4$\ 	ext{Pa}$$

Question 17

A river narrows from $$10\ 	ext{m}^2 to$$ $$2\ 	ext{m}^2 in $$cross-sectional area. If the speed of water in the wide section is $$1\ 	ext{m/s}$$, what is the speed in the narrow section?

Accepted Answer

$$5\ 	ext{m/s}$$

Question 18

Which of the following statements about Pascal’s Principle is correct?

Accepted Answer

An increase in pressure applied to a confined fluid is transmitted undiminished throughout the fluid.

Question 19

A closed tube contains air and is $$0.85\ 	ext{m}$$ long. What is the frequency of the second harmonic? (Speed of sound $$v = 340\ 	ext{m/s})$$

Accepted Answer

$$300\ 	ext{Hz}$$

Lecture 15

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드