Physics Exam 3
A 0.5-m long metal rod is heated from 25.0 °C to 100 °C. The length of the rod is found to be
elongated to 0.530 m. What is the coefficient of linear expansion of the metal? - ANS-d= 8 x
10^-4 k^-1
\A car engine has an efficiency of 30.0% and produces 4000 J of work. How much heat is
rejected by the engine? - ANS-
\A copper wire is connected between two glass jars. One of the jar is filled with ice cubes,
while the other jar is filled with boiling water. The amount of heat the flows through the wire
via conduction during a time interval t is not dependent on which of the following
parameters? - ANS-mass of the wire
\a flat metal washer has a 3mm circular hole in the center. When the metal washer is heated
- ANS-the hole diameter increases
\A hydraulic jack piston has a diameter of 0.06 m. The hydraulic jack is connected to another
piston that supports the load. The support load piston has a diameter of 0.50 m. If the jack
can lift a mass up to 2500 kg, what is the maximum force that one needs to apply to the
piston in order to lift the given mass? - ANS-wrong
\A large metallic cylindrical barrel with a diameter of 4 m lies 25.0 m below the surface of
Lake Lewisville. What is the magnitude of the force that acts on the square top of that
container? - ANS-Force = 3.08 x 10^6 N
\A man has trapped himself in an isolated room. The room can be assumed as a system.
The man walks inside the room for 5 hours and does 1250 J of work. In the process, his
internal energy decreased by 2250 J. Determine the amount of heat (Q) including the
algebraic sign exchanged between the system and the surrounding environment. What will
happen to the internal energy of the man if the system gains about 3000 J of heat from the
environment while performing the same amount of work? - ANS-
\a metal wire of length 5.0 mm was heated to 100 C from the room temperature. It was found
the length of the wore has increased to 5.05mm. This behavior is an example of which one
of the following material properties? - ANS-thermal expansion
\A schoolboy is trying to pump up a bicycle tire so that its pressure is 0.6 × 105 Pa above
that of atmospheric pressure. If the boy uses a hand-pump with a circular piston 0.025 m in
diameter, how much force he should apply? - ANS-Force = 29.43N wrong
\A solid object can float on water based on which of the following situations - ANS-if the
objects density is less than the density of water
\A system, while at a constant pressure of 2.5×105 Pascal, gains heat such that the work
done by the system is 4500 J. How much change will happen to the total volume of the
system? - ANS-
\A wooden room has a 0.16-m thick wooden floor [k = 0.141 W/(m · C°)] with an area of 20
m2. A fire keeps the interior of the room at a comfortable 20.0 °C while the air temperature in
the crawl space below the room is -10.0 °C. What is the rate of heat conduction through the
wooden floor? - ANS-528.75 W
\a) Calculate the rate of heat transfer by radiation from a car radiator at 110.0 °C into a 40.0
°C environment, if the radiator has an emissivity of 0.750 and a 1.2-m2 surface area. (b) Is
this a significant fraction of the heat transfer by an automobile engine? To answer this,
A 0.5-m long metal rod is heated from 25.0 °C to 100 °C. The length of the rod is found to be
elongated to 0.530 m. What is the coefficient of linear expansion of the metal? - ANS-d= 8 x
10^-4 k^-1
\A car engine has an efficiency of 30.0% and produces 4000 J of work. How much heat is
rejected by the engine? - ANS-
\A copper wire is connected between two glass jars. One of the jar is filled with ice cubes,
while the other jar is filled with boiling water. The amount of heat the flows through the wire
via conduction during a time interval t is not dependent on which of the following
parameters? - ANS-mass of the wire
\a flat metal washer has a 3mm circular hole in the center. When the metal washer is heated
- ANS-the hole diameter increases
\A hydraulic jack piston has a diameter of 0.06 m. The hydraulic jack is connected to another
piston that supports the load. The support load piston has a diameter of 0.50 m. If the jack
can lift a mass up to 2500 kg, what is the maximum force that one needs to apply to the
piston in order to lift the given mass? - ANS-wrong
\A large metallic cylindrical barrel with a diameter of 4 m lies 25.0 m below the surface of
Lake Lewisville. What is the magnitude of the force that acts on the square top of that
container? - ANS-Force = 3.08 x 10^6 N
\A man has trapped himself in an isolated room. The room can be assumed as a system.
The man walks inside the room for 5 hours and does 1250 J of work. In the process, his
internal energy decreased by 2250 J. Determine the amount of heat (Q) including the
algebraic sign exchanged between the system and the surrounding environment. What will
happen to the internal energy of the man if the system gains about 3000 J of heat from the
environment while performing the same amount of work? - ANS-
\a metal wire of length 5.0 mm was heated to 100 C from the room temperature. It was found
the length of the wore has increased to 5.05mm. This behavior is an example of which one
of the following material properties? - ANS-thermal expansion
\A schoolboy is trying to pump up a bicycle tire so that its pressure is 0.6 × 105 Pa above
that of atmospheric pressure. If the boy uses a hand-pump with a circular piston 0.025 m in
diameter, how much force he should apply? - ANS-Force = 29.43N wrong
\A solid object can float on water based on which of the following situations - ANS-if the
objects density is less than the density of water
\A system, while at a constant pressure of 2.5×105 Pascal, gains heat such that the work
done by the system is 4500 J. How much change will happen to the total volume of the
system? - ANS-
\A wooden room has a 0.16-m thick wooden floor [k = 0.141 W/(m · C°)] with an area of 20
m2. A fire keeps the interior of the room at a comfortable 20.0 °C while the air temperature in
the crawl space below the room is -10.0 °C. What is the rate of heat conduction through the
wooden floor? - ANS-528.75 W
\a) Calculate the rate of heat transfer by radiation from a car radiator at 110.0 °C into a 40.0
°C environment, if the radiator has an emissivity of 0.750 and a 1.2-m2 surface area. (b) Is
this a significant fraction of the heat transfer by an automobile engine? To answer this,
