Physics Exam 3
An athlete doing push-ups performs 650 kJ of work and loses 425 kJ of heat. What is the change in the internal (thermal) energy of the athlete?
-1075 kJ
An ideal gas undergoes an adiabatic process while doing 25 J of work. What is the change in internal energy ?
-25 J
During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the work done in the process?
-5.0 J
In an isochoric process, the internal energy of a system decreases by 50 J. What is the heat exchange?
-50 J
A mass of 0.350 kg is attached to a spring with a force constant of 3.58 N/m and undergoes simple harmonic oscillations with amplitude of 7.50 cm. What is the total mechanical energy of the system?
0.0101 J
A balloon inflated with helium gas has a volume of 6x10^-3 m^3. If the density of air is 1.3 kg/m^3, what is the buoyant force exerted on the balloon?
0.08 N
150 kcal of heat raises the temperature of 2.0 kg of material by 400 degrees F. What is the materials specific heat capacity?
0.34 kcal/ kg C
What is the carnot cycle efficiency for a system that operates with low temperature reservoir at 20º C and a high temperature reservoir at 200 ºC?
0.380
In the figure, the frequency is
0.5 Hz
A mass of 0.200 kg is attached to a spring with a force constant of 2.75 N/m and undergoes simple harmonic oscillations. What is the frequency of the oscillations?
0.592 Hz
What is the total energy of a 450 g mass that is attached to a horizontal spring with a force constant of 260 N/m and oscillates along a frictionless horizontal surface with amplitude of 8.0 cm?
0.83 J
The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the water pressure at that point? The density of seawater is 1025 kg/m^3.
1.11x10^8 Pa
The coefficient of linear expansion of steel is 12x10^-6 K^-1. What is the change in length of a 25 m steel bridge span when it undergoes a temperature change of 40 K?
1.2 cm
You drop a stone down a well that is 9.5 m deep. How long is it before you hear the splash? The speed of sound in air is 343 m/s and air resistance is negligible.
1.4 s
A 45.0 kg sample of ice is at 0.00 C. How much heat is needed to melt it? For water Lf= 334,000 J/kg and Lv= 2.256x10^6 J/kg
1.50 x 10^4 kJ
A simple pendulum of length 2.00 m is used to measure the acceleration of gravity at the surface of a distant planet. If the period of such a pendulum is 7.00s, what is the acceleration of gravity?
1.61 m/s^2
A wave has an amplitude 20.0 cm, a wavelength 3.00 m, and the wave travels 60.0 m in 12.0 s. What is the frequency of the wave?
1.67 Hz
A mass of 0.200 kg is attached to a spring with a force constant of 2.75 N/m and undergoes simple harmonic oscillations. What is the period of the oscillations?
1.69 s
A 500 N weight sits on the small piston of a hydraulic machine. The small piston has area 2.0 cm^2. If the large piston has area 40 cm^2, how much weight can the large piston support?
10,000 N
How much work is done by 3 moles of gas when they triple their volume at a constant temperature of 400K?
11.0 kJ
A 6.00 m long rope is under a tension of 600 N. Waves travel along this rope at 40 m/s. What is the mass of the rope?
2.25 kg
The weight of a 1200 kg car is supported equally by 4 tires, which are inflated to the same gauge pressure. What gauge pressure is required so the area of contact of each tire with the road is 100cm^2?
2.9x10^5 Pa
If 40 kcal of heat is added to 2.0 kg of water, what is the resulting temperature change? (waters specific heat capacity is 4186 J/kg C, 1kcal=4186 J)
20 C
200 J of work is done in compressing a gas adiabatically. What is the change in internal energy of gas?
200 J
An ideal gas occupies 400 L at an absolute pressure of 500 kPa, Find the absolute pressure if the volume changes to 950 L and the temperature remains constant
210 kPa
A perfect carnot engine operates between 350 K and 600 K. The engine delivers 10 kJ of work in each cycle. How much heat is extracted from the 600K reservoir in one cycle?
24 kJ
A 0.250 kg stone is attached to an ideal spring and undergoes simple harmonic oscillations with a period of 0.640 s. What is the force constant (spring constant) of the spring?
24.1 N/m
What is the temperature of 3.00 moles of an ideal gas at a pressure of 250 kPa held in a volume of 25.0 L? (R= 8.31 J/mol K)
251 K
A perfect carnot engine operates between the temperature of 300K and 700K, drawing 60 kJ of heat from the 700K reservoir in each cycle. How much heat is dumped into the 300 K reservoir in each cycle?
26 kJ
The quartz crystal in a digital watch has a frequency of 32.8 kHz. What is the period of oscillation?
30.5 microseconds
The efficiency of a carnot engine is 35.0 %. What is the temperature of the cold reservoir if the temperature of the hot reservoir is 500K?
325 K
Internal human body temperature is often said to be normal at 98.6 F. What is this temperature on the Celsius scale?
37.0 C
Waves travel along a 100m length of string with a mass of 55g, which is held taut by a tension of 75 N. What is the speed of the waves?
370 m/s
In the figure, the amplitude is
4 m
An object is undergoing simple harmonic motion of amplitude 2.3 m. If the maximum velocity of the object is 10 m/s, what is the object's angular frequency?
4.3 rad/s
Gallium boils at 2205°C. What is the corresponding temperature in the Fahrenheit scale?
4001 F
A heat engine operating at maximum efficiency has an efficiency of 25%. The temperature of the cold reservoir is 300K. What is the temperature of the hot reservoir?
400K
How many moles of H20 molecules are in a 4.00 m^3 container at a pressure 8.00x10^5 N/m^2 and a temperature of 600 C?
441
What is the maximum theoretical efficiency possible for an engine operating between 100º C and 400º C?
45%
From the energy that is input into an engine on each cycle, 500 kJ of mechanical work are produced and 600 kJ of heat are exhausted into the environment. What is the efficiency of the engine?
45.5%
A carnot cycle operates with an efficiency of 0.60 between a low temperature heat bath at 20.0 ºC and a high temperature heat bath. What is the temperature of the high temperature heat bath?
460º C
A block with 5.0x10^-3 m^3 of volume is suspended from a wire and is completely under water. What buoyant force acts on the block? (pwater= 1000 kg/m^3)
49 N
A 13000 N vehicle is to be lifted by a 25 cm diameter hydraulic piston. What force needs to be applied to a 5.0 cm diameter piston to accomplish this?
520 N
A crying baby emits sound with an intensity of 8.0x10^-12 W/m^2. What is the intensity level for a set of quintuplets? The lowest detectable intensity is 1.0x10^-12 W/m^2?
56 dB
What is the frequency of a pressure wave of wavelength 2.5 m that is traveling at 1400 m/s?
560 Hz
A heat engine with an efficiency of 30.0 % performs 2500 J of work. How much heat is discharged to the lower temperature reservoir?
5830 J
An ideal gas has a pressure of 2.5 atm, a volume of 1.0 L at a temperature of 30.0 C. How many molecules are there in this gas? (R=8.31 J/mol K, 1.00 atm=101 spa, NA=6.022 x 10^23)
6.0 x10^22
What is the average kinetic energy of a nitrogen molecule in the air in a room in which the air temp is 17.0 C?
6.01 x 10^-21 J
What is the average kinetic energy per molecule of an ideal gas at a temperature of 300 K? Boltzmann's constant is k=1.38 x 10^-23 J/K.
6.2 x 10^-21 J
In 1851 Jean Bernard Leon Foucault demonstrated the rotation of the earth using a pendulum 11.0 m long, which was set up in the Paris observatory. What was the period of oscillation of the pendulum?
6.66 s
The sound level of a person talking at 1.0 m of distance is 60 dB. You are surrounded by five people all talking at the same time. What sound level are you being exposed to?
67 dB
An object has a volume of 4.0 m^3 and weighs 40,000N. What will its apparent weight be in water of density 1000 kg.m^3?
800 N
The drawing shows three containers filled to the same height with the same fluid. In which container, if any, is the pressure at the bottom greatest?
All containers have the same pressure.
How a ship floats is described in terms of
Archimedes' principle
The lift on an airplane wing is an application of
Bernoulli's principle
A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample?
It does not change
The hydraulic lift is an application of
Pascals principle
The absolute temperature of an ideal gas is directly proportional to which of the following quantities?
The average kinetic energy of its molecules
The drawing shows a graph of displacement x versus time t for simple harmonic motion of an object on a horizontal spring. Which one of the following answers correctly gives the magnitude v of the velocity and the magnitude a of the acceleration at points A and B in the graph?
VA=maximum, aA=0 m/s, VB=o m/s, aB=maximum
Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is increased, the hole will
always expand with the plate
You are driving a late model convertible at the 55 mph limit with its soft ragtop roof up and the windows closed. You observe that the roof
bows outward
Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is decreased, the hole will
contract
The process in which heat flows by the mass movement of molecules from one place to another is known as
convection
A mass on a spring undergoes SHM. When the mass passes through the equilibrium position, its instantaneous velocity...
is maximum
A mass on a spring undergoes SHM. When the mass is at its maximum displacement from equilibrium, its instantaneous velocity...
is zero
Salt water is denser than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the volume of water displaced in the salt water is
less
When both the pressure and the absolute temperature of an ideal gas are increased each by a factor of two, the volume occupied by the gas will
not change
By what primary heat transfer mechanism does the sun warm the earth?
radiation
If the pressure acting on an ideal gas at constant temperature is tripled, its volume is
reduced to one third
A chunk of ice (T=-20 degrees C) is added to a thermally insulated container of cold water (T= 0 degrees C). What happens to the container?
some of the water freezes and the chunks of ice get larger
A mass M is attached to a spring with spring constant k. When this system is set in motion with amplitude A, it has a period T. What is the period if the mass is doubled to 2M?
sqrt2T
Two systems are in thermal equilibrium. The two systems are at the same
temperature
When you blow some air above the upper face of a paper strip, the paper rises. This occurs because
the air above the paper moves faster and the pressure is lower.
Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?
the buoyant force is the same in both cases
50 cm^3 of wood is floating on water, and 50 cm^3 of iron is totally submerged. Which has the greater buoyant force on it?
the iron
Two metal spheres are made of the same material and have the same diameter, but one is solid and the other is hollow. If their temperature is increased by the same amount,
the two spheres remain of equal size
When a bimetallic strip is heated, the strip will bend toward the side
with the smaller coefficient of linear expansion
When a bimetallic strip is cooled, the strip will bend toward the side
withe the larger coefficient of linear expansion
During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas?
zero
In an isochoric process, the internal energy of a system decreases by 50 J. What is the work done?
zero