Answer:
a. -4.166 J/K
b. 8.37 J/K
c. 4.21 J/K
d. entropy always increases.
Explanation:
Given :
Temperature at hot reservoir , [tex]$T_h$[/tex] = 720 K
Temperature at cold reservoir , [tex]$T_c$[/tex] = 358 K
Transfer of heat, dQ = 3.00 kJ = 3000 J
(a). In the hot reservoir, the change of entropy is given by:
[tex]$dS_h= -\frac{dQ}{t_h}$[/tex] (the negative sign shows the loss of heat)
[tex]$dS_h= -\frac{3000}{720}$[/tex]
= -4.166 J/K
(b) In the cold reservoir, the change of entropy is given by:
[tex]$dS_c= \frac{dQ}{t_c}$[/tex]
[tex]$dS_c= \frac{3000}{358}$[/tex]
= 8.37 J/K
(c). The entropy change in the universe is given by:
[tex]$dS=dS_h+dS_c$[/tex]
= -4.16+8.37
= 4.21 J/K
(d). According to the concept of entropy, the entropy of the universe is always increasing and never decreasing for an irreversible process. If the entropy of universe decreases, it violates the laws of thermodynamics. Hence, in part (c), the result have to be positive.
Is a windmill that is not running, potential or kinetic?
What happens to the electrical energy that does not become light energy?
A. The lightbulb transforms it into mechanical energy,
B. The lightbulb transforms it into thermal energy.
C. Some of the energy is destroyed over time rather than being
conserved
D. New energy is produced in the system when the lightbulb creates
light energy
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Answer:
B
Explanation:
To solve this we must be knowing each and every concept related to electrical energy. Therefore, the correct option is option B among all the given options.
What is electrical energy?The work done by an electric charge is referred to as electrical energy. For time t seconds, if electricity I ampere passes throughout a conductor or any other conducting element with a potential differential v volts across it.
The kilowatt hour is both a practical as well as an economic unit of electrical energy. The basic commercial unit is the watt-hour, one and kilowatt hour equals 1000 watt hours. Electric supply providers charge their customers every kilowatt hour unit of electricity used. This kilowatt hour seems to be a BOT unit, or board of trade unit. The electrical energy that does not become light energy, the lightbulb transforms it into thermal energy.
Therefore, the correct option is option B among all the given options.
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A 7300N elevator is to be given an acceleration of 0.150g by connecting it to a cable of negligible weight wrapped around a turning cylindrical shaft.
If the shaft's diameter can be no larger than 12.0cm due to space limitations, what must be its minimum angular acceleration to provide the required acceleration of the elevator
Answer:
The value is [tex]\alpha = 24.5 \ rad/s^2[/tex]
Explanation:
From the question we are told that
The weight of the elevator is [tex]W = 7300 \ N[/tex]
The acceleration it is to be given is [tex]a = 0.150 \ g = 0.150 * 9.8 = 1.47 \ m/s^2[/tex]
The diameter of the shaft is [tex]d = 12.0 \ cm = 0.12 \ m[/tex]
Generally the radius is mathematically represented as
[tex]r = \frac{d}{2}[/tex]
=> [tex]r = \frac{0.12}{2}[/tex]
=> [tex]r = 0.06 \ m[/tex]
Generally the minimum angular acceleration is mathematically represented as
[tex]\alpha = \frac{a}{r}[/tex]
=> [tex]\alpha = \frac{1.47}{0.06}[/tex]
=> [tex]\alpha = 24.5 \ rad/s^2[/tex]
A crate of books rests on a level floor. To move it along the floor at a constant velocity, why do you exert less force if you pull it at an angle Ï above the horizontal than if you push it at the same angle below the horizontal?
Answer:should be a matter of vector analysis.
Pulling above the horizontal has less surface area for the opposing friction
Explanation:
A box of mass 7.0 kg is accelerated from rest across a floor at a rate of 2.0 m/s2 for 9.0 s .Find the net work done on the box. Express your answer to two significant figures and include the appropriate units.
Answer:
Explanation:
Step one:
given data
mass = 7kg
acceleration =2m/s^2
time= 9seconds
acceleration = velocity/time
velocity= acceleration *time
velocity=2*9
velocity= 18m/s
distance moved= velocity* time
distance= 18*9
distance=162m
we also know that the force on impulse is given as
Ft=mv
F=mv/t
F=7*18/9
F=126/9
F=14N
work done = Force* distance
work done=14*162
work=2268Joules
work= 2.27kJ
A golf ball hit off a tee on level ground, lands 62 m away 3.0 later. What was the initial velocity of the golf ball?
62×3.0
think so not sure
Suppose two parallel-plate capacitors have the same charge Q, but the area of capacitor 1 is A and the area of capacitor 2 is 2 A.If the spacing between the plates, d, is the same in both capacitors, and the voltage across capacitor 1 is V, what is the voltage across capacitor 2?Express your answer in terms of V but do not type in the symbol "V"
Answer:
V' = V/2
Explanation:
The voltage across a parallel plate capacitor is given as follows:
V = Q/C
where,
V = Voltage across capacitor
Q = Charge on Capacitor
C = Capacitance of Capacitor = A∈₀/d
Therefore,
V = Qd/A∈₀
where,
A = Area of plate
d = distance between plates
∈₀ = permittivity of free space
FOR CAPACITOR 1:
Q = Q
d = d
A = A
V = V
Therefore,
V = Qd/A∈₀ --------------- equation (1)
FOR CAPACITOR 2:
V' = ?
Q' = Q
d' = d
A' = 2A
Therefore,
V' = Q'd'/A'∈₀
V' = Qd/2A∈₀
V' = (1/2)(Qd/A∈₀)
using equation (1):
V' = V/2
is 2/2 1 or 0? please help lol
Answer:
1.
Explanation:
Hello!
In this case, for such mathematical operations, we can wee that the slash represents a fraction or a division, say 8 ÷ 4 = 2, 6 ÷ 3 = 2, 20 ÷ 4 = 5, etc. In such a way, since the operation 2/2, represents 2 ÷ 2, it is clear that two is once in 2, therefore, the result is:
2 ÷ 2 = 1.
Best regards!
a book weighing 1.0 newton is lifted 2m. how much work was done?
Answer:
Work done, W = 2 J
Explanation:
Given that,
Weight of a book, W = F = 1 N
It is lifted to a height of 2 m
We need to find the work done. It can be calculated using the formula as follows :
W = F d
Put all the values,
W = 1 N × 2 m
W = 2 J
So, 2J of work was done.
A conducting sphere has a net charge of -4.8x10-17 C. What is the approximate number of excess electrons on the sphere?
Answer:
The number is [tex]N = 300[/tex]
Explanation:
From the question we are told that
The net charge is [tex]Q = -4.8 *10^{-17 } \ C[/tex]
Generally the charge on a electron is [tex]e = - 1.60 *10^{-19 } \ C[/tex]
Generally the number of excess electrons is mathematically represented as
[tex]N = \frac{Q}{e}[/tex]
=> [tex]N = \frac{-4.8 *10^{-17}}{-1.60 *10^{-19}}[/tex]
=> [tex]N = 300[/tex]
A solid concrete block weighs 169 N and is resting on the ground. Its dimensions are
0.400m×0.200m×0.100m
A number of identical blocks are stacked on top of this one. What is the smallest number of whole blocks (including the one on the ground) that can be stacked so that their weight creates a pressure of at least two atmospheres on the ground beneath the first block?
Answer:
Explanation:
cross sectional area = .4 x .2 = .08 m²
Let n be the number of blocks required to make pressure = 2 atm
169 x n / .08 = 2 x 10⁵ N / m²
169 x n = .16 x 10⁵
n = 94.67
or 95 blocks .
Help!!! Need answer ASAP.
Answer:
a = 0.5 [m/s²]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces is equal to the product of mass by acceleration.
ΣF = m*a
F = force = 200 [N]
m = mass = 400 [kg]
a = acceleration [m/s²]
Now replacing:
200 = 400*a
a = 0.5 [m/s²]
What is the approximate horizontal velocity at which the boy in the diagram
threw the ball?
a. +5m/s
b. +20m/s
c. +25m/s
d. +30m/s
Answer:
D
Explanation:
5+25=30
2
10 points
Find the total displacement of each of the motions.
a) You walk 45 m W, then 34 mW
b) You drive 5 km N, then 7 km S
c) You cycle 350 m E, then 800 m W, then 200 m E
d) You fly 850 km N then 850 km S
Answer:
a) s = 79 m W
b) s = 2 km S
c) s = 250 m W
d) s = 0 km
Explanation:
We take the following sign convention for the directions:
North (N) ---> positive
South (S) ---> negative
East (E) ---> negative
West (W) ---> positive
a)
45 m W, 34 m W
s = 45 m + 34 m
s = 79 m W
b)
5 km N, 7 km S
s = 5 km - 7 km
s = - 2 km
s = 2 km S
c)
350 m E , 800 m W, 200 m E
s = -350 m + 800 m - 200 m
s = 250 m
s = 250 m W
d)
850 km N, 850 km S
s = 850 km - 850 km
s = 0 km
explain what the emitter does in CT
the emitter of x-rays rotates around the patient and the detector, placed in diametrically opposite side, picks up the image of a body section (beam and detector move in synchrony)
i believe that should be ur answer =) good luck !
A flat loop of wire consisting of a single turn of cross-sectional area 7.10 cm2 is perpendicular to a magnetic field that increases uniformly in magnitude from 0.500 T to 2.10 T in 1.07 s. What is the resulting induced current if the loop has a resistance of 1.60?
Answer:
The induced current is [tex]I = 0.00066 \ A[/tex]
Explanation:
From the question we are told that
The area is [tex]A = 7.10 \ cm^2 = 7.10 *10^{-4} \ m^2[/tex]
The initial magnetic field is [tex]B_i = 0.500 \ T[/tex]
The magnetic field after t =1.07 s is [tex]B_f = 2.10 \ T[/tex]
The resistance of the loop is [tex]R = 1.60 \ \Omega[/tex]
Generally the electromagnetic field induced is mathematically represented as
[tex]\epsilon = NA * \frac{B_f - B_i}{t}[/tex]
Where N is the number of turns which is 1 in the case of this question since there is only one loop
So
[tex]\epsilon = 1 * 7.10*10^{-4}* \frac{2.10 - 0.500}{1.07 }[/tex]
=> [tex]\epsilon = 0.00106 \ V[/tex]
Generally the value of the current is mathematically represented as
[tex]I = \frac{\epsilon}{R}[/tex]
[tex]I = \frac{0.00106}{1.60}[/tex]
[tex]I = 0.00066 \ A[/tex]
HELP ASAP!!!
Which graph shows the change in velocity of an object in free fall?
Answer:
the graph that show Change in velocity is no A
The graph that showing the velocity with respect to time for a free falling body is figure C where, the downward velocity will be higher due to the acceleration due to gravity.
What is velocity?Velocity of a moving body is the measure of the distance covered per unit time. Thus, it is the ratio of distance to the time. Velocity is expressed in the units of Km/h, m/s. miles/h, ft./s etc.
The rate of change of velocity is called acceleration. The acceleration by the force of a gravitational field is called acceleration due to gravity g having the value 9.8 m/s².
The velocity - time graph shows a diagonal relation for a free falling body. A free falling body is initially at rest and falls downward with the negative velocity with the acceleration due to gravity. Therefore, figure B shows the change in velocity of a free falling body.
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A 0.300 kg ball, moving with a speed of 2.5 m/s, has a head-on collision with at 0.600 kg ball initially at rest. Assuming a perfectly elastic collision, what will be the velocity of the small ball if the heavier ball has a speed of 2m/s after collision.
Answer:
1.25 m/s
Explanation:
Given,
Mass of first ball=0.3 kg
Its speed before collision=2.5 m/s
Its speed after collision=2 m/s
Mass of second ball=0.6 kg
Momentum of 1st ball=mass of the ball*velocity
=0.3kg*2.5m/s
=0.75 kg m/s
Momentum of 2nd ball=mass of the ball*velocity
=0.6 kg*velocity of 2nd ball
Since the first ball undergoes head on collision with the second ball,
momentum of first ball=momentum of second ball
0.75 kg m/s=0.6 kg*velocity of 2nd ball
Velocity of 2nd ball=0.75 kg m/s ÷ 0.6 kg
=1.25 m/s
A current of 3.75 A in a long, straight wire produces a magnetic field of 2.61 μT at a certain distance from the wire. Find this distance.
Given :
Current, I = 3.75 A .
Magnetic Field, [tex]B = 2.61\times 10^{-4}\ T[/tex]
To Find :
The distance from the wire.
Solution :
We know,
[tex]B = K\dfrac{2i}{d}\\\\d = 10^{-7}\times \dfrac{2\times 3.75}{2.61\times 10^{-4}}\\\\d = 0.00287\ m \\\\d = 2.87\times 10^{-3}\ m[/tex]
Hence, this is the required solution.
What will happen to the charge and potential difference if the plate area were increased while the plate separation remains unchanged?
Answer:
Potential difference and charge will also increase.
Explanation:
Asking that :
What will happen to the charge and potential difference if the plate area were increased while the plate separation remains unchanged?
The charge is directly proportional to area of the plate. That is, increase in area of the plate of a capacitor will lead to the increase in the charges between the plates.
And since charge is also proportional to the magnitude of potential difference between the plates from the definition of capacitance of a capacitor which says that:
Q = CV
Therefore, increase in the area of the plate will also lead to increase in potential difference between the plates.
Therefore, if the plate area were increased while the plate separation remains unchanged, the charge and potential difference between them will also increase.
why is it more painful to walk on gravel with your shoes off then on (3 marks please)
Answer:
Because shoes protect our feet from some of the most harmful platforms
Gravel has some small pebbles on it sometimes (or other sharp objects)
Gravel is pretty hard.
PLEASE HELP WITH A PHYSICS QUESTION!!!!
A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun straight down towards the water. If air resistance is negligible, how do the accelerations of the bullets compare just before they strike the water?
A. The acceleration is the same for both bullets.
B. The acceleration of the dropped bullet is greater.
C. The acceleration of the fired bullet is greater.
D. The comparison will depend on how high the bullets started.
Answer:
A. The acceleration is the same for both bullets.
Explanation:
The force of gravity is the attractive force applied by the earth on any object on its surface or neighborhood. And it is uniform under free fall at a definite location on the earth.
Since the the two bullets motion was at the same time and without air resistance, their acceleration would be the same before striking the surface of the water. This is because neglecting air resistance, all objects at the same height would fall with the same acceleration no matter their masses.
3.
A net force acting on an 8.0 kg box produces an acceleration of 3.5 m/s2. What acceleration will the same net force cause to a different box with a mass of 2.0 kg?
Answer:
13.5
Explanation:
The acceleration that the same net force would cause to a different box is 14 [tex]m/s^2[/tex].
Given the following data:
Mass of box A = 8 kg
Acceleration = 3.5 [tex]m/s^2[/tex]
Mass of box B = 2 kg
To find the acceleration that the same net force would cause to a different box:
First of all, we would determine the net force acting on box A by applying Newton's Second Law of Motion.
Mathematically, Newton's Second Law of Motion is given by the formula;
[tex]Net\;force = mass \times acceleration\\\\Net\;force = 8 \times 3.5[/tex]
Net force = 28 Newton.
Now, we can determine the acceleration for box B since the same net force act on it.
[tex]Acceleration = \frac{Net\;force}{mass} \\\\Acceleration = \frac{28}{2 }[/tex]
Acceleration = 14 [tex]m/s^2[/tex]
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At an air show a jet flies at speed 1500 km/h on a day when the speed of sound is 342 m/s. What is the angle of the shock cone
Answer:
55 degrees
Explanation:
Given that an air show a jet flies at speed 1500 km/h on a day when the speed of sound is 342 m/s.
From the question above, we can get the below parameters
Object speed (V) = 1500 km/h
Sound speed ( v) = 342 m/s
Convert km/h to m/s
(1500 × 1000)/3600
Jet speed V = 416.67 m/s
Let's first calculate the mash number M.
M = V/v
M = 416.67 / 342
M = 1.2183
Formula for the angle of the shock cone is reciprocal of mash number. That is,
Sin Ø = 1 / M
Sin Ø = 1 / 1.2183
Sin Ø = 0.8208
Ø = sin^-1(0.8208)
Ø = 55 degree
Therefore, the angle of the shock cone is approximately 55 degrees
what is primary purpose of Pathfit?
Answer:
to show the arts and creativity of the person and to show also the culture of the place..
Explanation:
How much would a spring scale with k = 120 N/m stretch, if it had a 3.75 J of work done
on it?
Answer:
0.25m
Explanation:
Given parameters:
Spring constant , K = 120N/m
Work done = 3.75J
Unknown:
magnitude of extension = ?
Solution:
To solve this problem;
Work done = [tex]\frac{1}{2}[/tex]kx²
K is the spring constant
x is the extension
3.75 = [tex]\frac{1}{2}[/tex] x 120x²
3.75 = 60x²
x² = 0.06
x = √0.06 = 0.25m
Which energy transformation occurs after a skydiver reaches terminal velocity? Gravitational potential energy transforms into thermal energy. Gravitational potential energy transforms into kinetic energy. Kinetic energy transforms into thermal energy. Kinetic energy transforms into gravitational potential energy. The answer is A. just took it
Answer:
a
Explanation:
The energy transformation occurs after a skydiver reaches terminal velocity is follows as;
A. Gravitational potential energy transforms into thermal energy.
B. Gravitational potential energy transforms into kinetic energy.
What is the gravitational potential energy?The skydiver, when he is located at a certain height h above the ground, possesses gravitational potential energy, equal to:
U = mgh
where m is the mass of the skydiver, g is the gravitational acceleration and h is the height above the ground.
The skydiver gravitational potential energy decreases as the altitude decreases and his kinetic energy store increases as his speed increases.
When a skydiver jumps out of a plane, the energy transfers take place as;
The skydiver's kinetic energy store increases as their speed increases and the thermal store of the air and the skydiver increases, as there is friction between the skydiver and the air particles.
In the given situation, both options A and B are correct.
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How do we use energy transformation in our daily lives?
Answer:hat are some examples of energy transformation?
The Sun transforms nuclear energy into heat and light energy.
Our bodies convert chemical energy in our food into mechanical energy for us to move.
An electric fan transforms electrical energy into kinetic energy.
Explanation:
how does the uneaven heating of earths surface affects earths weather patterns
Answer: it causes some parts of the earth to get more radiation than others.
Explanation: earth rotates around the sun on a tilted axis so the Rays of the sun cause earth to have more radiation than it needs.
Which theory explains why gravity between two objects changes when the distance between them changes?
Einstein's theory because he suggested that the more distance there is between objects, the more space-time
curves and the greater the strength of gravity is.
Einstein's theory because he suggested that the more distance there is between objects, the more space-time
curves and the weaker the strength of gravity is.
Newton's theory because he suggested that the greater the distance between objects, the greater the pull of gravity.
Newton's theory because he suggested that the greater the distance between objects, the weaker the pull of gravity.
Answer:
Newton's theory because he suggested that the greater the distance between objects, the weaker the pull of gravity.
Answer: The answer is Newton’s theory because he suggested that the greater the distance between objects, the weaker the pull of gravity
Explanation: Just took the test i hope this help you enjoy :D