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Gravity
Terms in this set (90)
Three drinking glasses of different shapes - which has the greatest liquid pressure at the bottom?
All three have equal pressure
What is the difference between pressures inside and outside a bicycle tire?
Guage pressure
A piece of wood is floating in a tub of water. a second piece of wood rests on top of the first; it does not touch the water. If the second piece is removed from the first and placed in the water, what happens to the water level in the tub?
The water level remains unchanged
A cube of wood is floating on water. A cube of iron is totally submerged in water. The cubes are equal in volume. Which cube has the greater buoyant force acting on it?
The cube of iron has the greater buoyant force acting on it because it displaces more fluid
Water flows through a horizontal pipe. The diameter of pipe B is larger than the diameter of the pipe at point A. Where is the water pressure the greatest?
Point B.
Which of the 3 phases of matter has a fixed volume?
Liquid and solid
Which is considered a fluid?
Gas and liquid
Which of the following is associated with the law of conservation of energy in fluids?
Bernoulli's principle
An ideal fluid flows at 12 m/s in a horizontal pipe. If the pipe widens to twice its original radius, what is the flow speed in the wider section?
3 m/s
If the density of gold is 19.3x10^3 kg/m3, what buoyant force does a 0.60-kg gold crown experience when it is immersed in water?
0.30 N
A circular window of 30 cm diameter in a submarine can withstand a maximum force of 5.20x10^5 N. What is the maximum depth in a lake to which the submarine can go without damaging the window?
750 m
Density is...?
proportional to mass and inversely proportional to volume
What was the main purpose of the demonstration with floating diet coke and a sinking regular coke?
Archimede's Principle
what term denotes the time for one cycle of a periodic process?
period
what is the period of a simple pendulum 88 cm long on the Earth in a free falling elevator?
0
A mass on the end of a spring undergoes simple harmonic motion. At the instant when the mass is at its maximum displacement from equilibrium, what is its instantaneous velocity?
Zero
At maximum displacement, its instantaneous velocity is zero
the frequency of a wave increases. If the speed of the wave remains constant, what happens to the distance between successive crests?
Decreases
What was the main purpose of the pendulum wave demo?
That the length of the string determines the period of a simple pendulum
Doubling the amplitude of a vibrating mass and spring system produces what effect on the system's mechanical energy?
Increases the energy by a factor of four
A mass oscillates on the end of a spring and bobs up and down between points A and B. Where is the mass located when its kinetic energy is at max?
midway between A and B
A mass oscillates on the end of a spring, both on Earth and on the Moon. Where is the period the greatest?
The same on the Earth and Moon
The maximum gauge pressure in a hydraulic lift is 15.8 atm. What is the largest size vehicle (kg) it can lift if the diameter of the output line is 28.1 cm?
10100 kg
Describe the physics that explains lift on an airplane blade as described by Bernoulli's equation. Add air stream lines and labels to the following diagram and support your explanation..?
..?
An elastic cord vibrates with a frequency of 3.2 Hz when a mass of 0.59 kg is hung from it. what is its frequency when only 0.40 kg hangs from it?
3.9 Hz
What is the period of a simple pendulum 88cm long on the Earth? What is the period of a simple pendulum 80 cm long when it is in a freely falling elevator?
1.9 s, no period
A sound wave in air has a frequency of 263 Hz and travels with a speed of 350 m/s. How far apart are the crests?
1.33 m
Two wave pulses pass each other on a string. The pulse traveling toward the right has a positive amplitude, and the pulse traveling toward the left has an equal positive amplitude. What happens when they occupy the same region of space at the same time?
Constructive interference
A standing wave is established on a string that is fixed at both ends. if the string is vibrating at its fundamental frequency, how is the length of the string related to the wavelength of the standing wave?
the length of the string is equal to 1/2 of the wavelength
A guitar player shortens the length of a guitars vibrating string by pressing the string straight down onto a fret. the guitar then emits a higher pitched tone because ?
the string vibrates at a higher frequency
refraction is caused by?
different wave speeds
which of the following is true?
the loudness of the sound is related to its amplitude
in general, sound is conducted fastest through..?
solids
in order to produce beats, the two sound waves should have..?
slightly different frequencies
the following image represents a sound source moving ---- than the speed of the sound wave
slower
a sound source approaches a stationary observer. the frequency heard by the observer is?
higher than the source
Rod A has twice the diameter of Rod B, but both are made of iron and have the same initial length. Both rods are now subjected to the same change in temperature but remain solids. how would the rods length compare?q
Rod A = Rod B
a flat metal washer is heated. as the washer's temperature increases, what happens to the hole in the center?
the hole in the center will expand
if the pressure acting on a given sample of an ideal gas at constant temperature is tripled, what happens to the volume of the gas?
1/3 of its original value
which two temperature changes are equivalent?
1 C = 1 K
to the nearest degree, what is absolute zero on the celsius scale?
-274 C
both the pressure and volume of a given sample of an ideal gas double. this means that its temperature in Kelvin must..?
quadruple
the average molecular kinetic energy of a gas can be determined by knowing only
the temperature of the gas
express your body temp in C degrees (98.6 F)
37.0 C
to the nearest degree, if room temp is 65 degrees, what is it in C?
18 C
a thermally isolated system consists of a hot piece of aluminum and a cold piece of copper. the aluminum and copper are in thermal contact. the specific heat of aluminum is more than double that of copper. which object experiences the greater amount of heat transfer during the time it takes the system to reach thermal equilibrium?
both experience the same magnitude of heat transfer
the amount of heat necessary to raise the temp of 1 g water by 1 C is referred to as the
calorie
it is a well known fact that water has a higher specific heat capacity than iron. now, consider equal masses of water and iron are initially in thermal equilibrium. the same amount of heat, 30 cal, is added to each. what is true?
they are no longer in thermal equilibrium; the iron is warmer
phase changes occur..?
as the temp remains the same
a typical thermos bottle has a thin vacuum space between the shiny inner flask (which holds liquid) and the shiny protective outer flask, often stainless steel. the vacuum space is excellent at preventing..
conduction and convection
by which primary heat transfer mechanism does one end of a steel rod become hot when the other end is placed in a flame?
conduction
which of the following best explains why sweating is important to humans maintaining suitable body temp?
evaporation of moisture from the skin extracts heat from the body
spaceship where acceleration is 0, convection currents
no conventional convection currents
calculate the wavelengths in air at 20 C for sounds in the maximum range of human hearing, 20 Hz to 20,000 Hz (the speed of sound in air at 20 C is 343 m/s)
17 m
explain the doppler effect
--
the steel bed of a suspension bridge is 300m long at 25 C. if exposed to -20 C to 350 C, how much will it contract and expand?
--
explain why a pressure cooker cooks food in less time than a regular pot that is not able to hold pressure. use the words and the P-T diagram for water.
--
a concrete highway is built of slabs 14m long (20 C). How wide should the expansion cracks between the slabs be at 20 C to prevent buckling if the range of temp is -30 C to 45 C? The coefficient of linear expansion of concrete is 12x10^-6 1/C
4.2 x 10-3 m
explain the difference between temp and heat. describe the demo that was used in class to show what temp is on a molecular level
--
a hot iron horseshoe (mass 0.40 kg) just forged is dropped into 1.35 kg of water in a 0.30 kg pot initially at 20 C. If the final equilibrium temp is 25 C, estimate the initial temp of the hot horseshoe. Specific heat of iron = 450 J/kg C. SH of water is 4186 J/kg C
186 C
which of the following are possible statements of the 2nd law of thermodynamics?
All Carnot engines operating between the same two temperatures have the same efficiency, irrespective of the nature of the working substance
how is thermal efficiency of a heat engine defined?
the ratio between the work performed and the heat input at the higher temperature
in order for the efficiency of a Carnot engine to reach 100%, what would the temp of the cold reservoir be?
absolute zero
is it possible to transfer heat from a cold reservoir too a hot reservoir?
yes, if work is done
the efficiency of a heat engine is defined as the ratio of
the work it does to the heat input at the high temperature
when water freezes, the entropy of the water
decreases
a heat engine receives 7000 J of heat and loses 3000 J in each cycle. What is the efficiency?
57%
A positively charged rod is brought close to one end of a metal rod but does not actually touch it. What type of charge does the end of the metal rod closest to the positively charged rod acquire?
the end of the metal rod closest to the positively charged rod acquires a negative charge
two charged objects are separated by some distance. the charge on the first object is greater than the charge on the second object. how does the force between the two objects compare?
the first object exerts a large electrostatic force on the second object
two charged objects are separated by some distance. the charge in the first object is greater than the charge on the second object. how does the force between the two objects compare?
the charged objects exert electrostatic forces on each other that are equal in magnitude and opposite in direction
two charged objects are separated by some distance attract each other. if the charges on both objects are tripled with no change in distance between them, what happens to the magnitude of the force between the objects?
the force between them increases by a factor of 9
which is true?
electric field lines near positive point charges radiate outward
If Q1 is negative and has a magnitude less than Q2, which is positive, where could a positive charge be placed and possibly have a zero net force on it?
Point A
is it possible for the electric field between two positive charges to equal zero along the line joining the two charges?
yes, regardless of the magnitude of the two charges
sphere A carries a net positive charge, and sphere B is neutral. They are placed near each other on an insulated table. Sphere B is briefly touched with a wire that is grounded. Which is correct?
sphere B is now negatively charged.
a positive object touches a neutral electroscope and the leaves separate. then a negative object is brought near the electroscope, but does not touch it. what happens to the leaves?
they move closer together
if the voltage across a circuit of constant resistance is doubled, how is the current in the circuit affected?
doubled
a circuit maintains constant resistance. if the current in the circuit is doubled, how is the power in the circuit affected?
the power dissipated is quadrupled
in the war of the currents, when electrification first began, which method did Tesla support?
Alternating current
consider 2 copper wires. one has twice the cross sectional area of the other. how do the resistances of those two wires compare?
the thicker wire has half the resistance of the thinner wire
draw the schematic for the heat engine. include high temperature and low temp reservoir, add flows of heat or work
---
3 possible sources of heat for Rankine engine
nuclear
geothermal
coal
solar
what is the change in entropy of 3.00 m3 of water at 0 C when it is frozen to ice at 0 C?
-3.66 x 10^6 J/K
suppose that 4 equal negative charges are located at the corners of a square. using arrows, indicate the direction of the electric field at each midpoint and the center
--
A test charge of 6x 10^-6 C experiences a downward electrostatic force of 12 N when placed at a certain point in space. what are the magnitude and direction of the electric field at this point?
2.0 x 10^6 N/C down
determine the resistance of, and current through, a 75 W light bulb connected to its proper source of voltage of 120 V.
R = 192 ohms
I = 0.625 A
Which is a statement of Ohm's Law
V = IR
as more devices are added to a series circuit, the total resistance for the circuit increases
True
a device that converts mechanical energy to electrical energy is a
generator
for a simple magnet, like poles attract
false
typically for a large generator, the magnet "field" would be located on the ?
Rotor
;