PHY 171 - Midterm

Question 1

What are the SI units for density? What is the formula?

Answer 1

rho = m/v

SI unit = kg/m^3

Question 2

What is 1 g/cm^3 in 1000 kg/m^3?

Answer 2

1000 kg/m^3

Question 3

What is 1 m^3 in L?

Answer 3

1000 L

Question 4

What formula and SI unit for pressure?

Answer 4

P = F/A

SI unit = 1 N/m^2

Question 5

What is the nature of pressure in fluids?

Answer 5

pressure is everywhere, pushes all ways equally

Question 6

How does pressure change with depth in a liquid?

Answer 6

pressure increases with depth

Question 7

In a liquid, does pressure vary across a horizontal line?

Answer 7

no

Question 8

What is the equation for guage pressure?

Answer 8

pg = p - 1 atm

Question 9

What is the solving strategy for a connected liquid?

Answer 9

set them equal to eachother

Question 10

What is Archimedes’ Principle?

Answer 10

a fluid produces an upward buoyant force

Question 11

What is equal to the magnitude of the buoyant force?

Answer 11

weight of the fluid displaced or desnity of fluid * volume submerged * grav constant

Question 12

What determines if an object floats are sinks?

Answer 12

how the buoyant force compares to its weight (depends on density)

Question 13

What is the equation of continuity for fluid dynamics and what does it indicate?

Answer 13

v1A1 = v2A2

• flow is faster in a narrower tube
• flow is slower in a wider tube

Question 14

T/F: The flow rate of a dynamic fluid is constant.

Answer 14

True, Q = vA

Question 15

What is Bernoulli’s equation mean in terms of energy?

Answer 15

it is the conservation of energy for fluids

Question 16

How do wider sections of a tube with a dynamic fluid affect the pressure?

Answer 16

Pressure increases in wider spaces and decreases in narrower spaces

Question 17

In a monometer, if the right side fluid is higher than the left, is rhogh positive or negative?

Answer 17

positive

Question 18

What is oscillatory motion?

Answer 18

repetitive motion back and forth around an equilibrium position

Question 19

What is simple harmonic motion?

Answer 19

sinusoidal oscillations (ex. mass on a spring)

Question 20

What does the slope of a F vs position graph give?

Answer 20

the restoring force of a spring

Question 21

What is a phase?

Answer 21

an angle of circular motion whose shadow matches oscillator and increases with time

Question 22

If the value for the phase constant is between 0 and pi, is it positive or negative?

Answer 22

negative

Question 23

if the value of the phase constant is between pi and 2pi, is it positive or negative?

Answer 23

positive

Question 24

Where does an oscillating object have purely PE and purely KE?

Answer 24

purely PE at x = +/- A

purely KE at x = 0 (equilibrium)

Question 25

Do period and frequency depend on amplitude for simple harmonic motion?

Answer 25

no

Question 26

What is the equation for the restoring force of a pendulum?

Answer 26

F = -mgsin(theta)

Question 27

What do the frequency and period of a pendulum depend on and not depend on?

Answer 27

depend on length of pendulum | does not depend on mass

Question 28

What quantity must a physical (torsional) pendulum incorporate?

Answer 28

moment of inertia (I)

Question 29

What are damped oscillations?

Answer 29

oscillations that slow down and stops due to external force

Question 30

How does the envelope of damped oscillations decay?

Answer 30

exponentially

Question 31

REMINDER:

Answer 31

fill in damped, lightly, heavily here!!

Question 32

What is a driven oscillatin?

Answer 32

oscillator subjected to periodic external force

Question 33

What is resonance?

Answer 33

large-amplitude response to driving force due to driving force frequency matching that of system (fext = fo)

Question 34

What does a lightly damped peak with resonance look like on a resonance curve?

Answer 34

tall and skinny

Question 35

What is a traveling wave?

Answer 35

organized disturbance traveling with well defined speed

Question 36

What is a transverse wave?

Answer 36

wave in which displacement is perpendicular to direction of travel (ex. electromagnetic)

Question 37

What is a longitudinal wave?

Answer 37

displacement is parallel to direction of travel

Question 38

Do mechanical waves require a medium?

Answer 38

yes

Question 39

How is wave speed increased ?

Answer 39

increasing tension or decreasing string density

Question 40

What does a snapshot graph show and what are its axes?

Answer 40

``` x = position y = displacement ``` shows wave pulse (actual picture)

Question 41

What does a history graph show and what are its axes?

Answer 41

``` x = time y = displacement ``` shows history of a particular point in medium (leading edge is closes to y-axis)