Answer:
The entropy change is 45.2 kJ/K.
Explanation:
mass of water at 100 C = 2 kg
Latent heat of vaporization, L = 2260 kJ/kg
Heat is
H = m L
H = 2 x 2260 = 4520 kJ
Entropy is given by
S = H/T = 4520/100 = 45.2 kJ/K
The entropy change during the phase change of water from liquids to steam at constant pressure and same temperatures will be zero because, Δ T is zero here.
What is entropy?Entropy is a thermodynamic parameter determining the measure of randomness in a system. Entropy of a natural reaction or change is always increasing.
According to second third law of thermodynamics the entropy change of the universe is positive always. At constant pressure the entropy change a of substance of m g is written as:
ΔS = m Cp ln T2/T1.
Where Cp is the specific heat capacity at constant pressure.
Here, the initial temperature and final temperature is same 100 degree celsius. Thus T2/T1 becomes 1 and log 1 is zero. Therefore, the entropy change in this phase change is zero.
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Why is it difficult to maintain constant speed of a vehicle?
Answer:
The road surface is always rough, so the frictional force between the tires and the road surface make it difficult to maintain constant speed because acceleration always changes.
Write down the role played by four digestive juices in digestion and the
organs which secrete them.
Answer:
Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar
Explanation:
Two rams run toward each other. One ram has a mass of 44 kg and runs south with a speed of 6 m/s, while the other has a mass of 50 kg and runs north with a speed of 3 m/s. What will the momentum of the system made up of the two rams be after they collide? Assume the total momentum of the system is conserved.
A. 114 kg-m/s south
B. 414 kg-m/s south
C. 414 kg m/s north
D. 114 kg-m/s north
An electron enters the magnetic field at right angle from left B into paper. The electron will be deflected?
Answer:
According to this direction of force is perpendicular to the direction of current and magnetic field. Therefore force is opposite to electron into the paper at 90°.
An iron weight, suspended by a string, is motionless. The tension
in the string is 4.75 newtons. What is the mass of the iron
weight?
Answer:
Explanation:
If the mass hangs at the end of the string and the string can support the mass and doesn't break, and the mass hangs still, that means that the tension in the string is equal to the downward pull of the mass. However, we are given the tension in Newtons and the mass needs to be in kg. So we use the equation for weight:
w = mg where w, the weight, is the same as the tension in the string. Gravity is always 9.8 in the metric system:
4.75 = m(9.8) so
m = .48 kg
Answer:
Answer: A
0.485 Kg
Explanation:
A girl walks 55 m downhill in 3.2 s. What is her average velocity?
Answer:
V = 17.2
Explanation:
Speed = distance(m) / time(s)
= 55m / 3.2s
=17.2 m/s
Tính công của dòng điện
Answer:
CG gh sure er go b vh pxuh FPI OO c AM h kh
An object of mass 10 kg has a momentum of 15 kg m/s. Find the average force required to accelerate the object to 10 m/s over 20 seconds.
Answer:
Force = 4.25 Newton
Explanation:
Given the following data;
Mass = 10 kg
Momentum = 15 Kgm/s
Time, t = 20 seconds
Final velocity, V = 10 m/s
To find the average force required;
First of all, we would determine the initial velocity of the object.
Momentum = mass * velocity
15 = 10 * velocity
Velocity = 15/10
Velocity = 1.5 m/s
Next, we would determine the acceleration of the object by using the first equation of motion;
V = U + at
10 = 1.5 + a*20
10 - 1.5 = 20a
8.5 = 20a
Acceleration, a = 8.5/20
Acceleration, a = 0.425 m/s²
Lastly, we would find the average force by using the formula;
Force = mass * acceleration
Force = 10 * 0.425
Force = 4.25 Newton
When developing an experiment design, which could a scientist take to improve the quality of the results?
The options missing are;
A. Make only a few changes to the manipulated variable.
B. Identify any biases about the answer to the scientific question.
C. Include as many details as possible when writing the conclusion.
D. Share her ideas through peer review.
Answer:
B. Identify any biases about the answer to the scientific question.
Explanation:
Since the question is asking what can be done to improve the quality of the results, it means what can the scientist do to make sure that the result answers the question properly and has little or no biases.
Thus, looking at the options, the only one that comes close to actually improving on the quality of the results before finalizing is option B where the scientist is to identify any biases.
State any ten reasons why students in Uganda need to study physics?use examples of the possible technological advancements which can be made using the knowledge of physics
Answer:
1.it also hleps us to became doctors becuase without physics you can't be a doctor
2.physics needs to be steady whether you like it or not it helps you in life so everybody must study physics no matter is in Uganda USA and plenty more countries there must be physics to dare to be studied
what is momentum
what is momentum in words
Answer:
It's a strength or force
Explanation:
the quantity of motion of a moving body, measured as a product of its mass and velocity
Answer:
momentum is a quality define as the product of the mass and velocity of an object.
(d) Below shows a hydraulic press with a pump piston of area 4 cm2 and a ram area of
12 cm2 . IF A force of 300 N is applied on the pump piston, find:
(i)the maximum load on the ram.
(ii) the velocity ratio of the machine.
(iii) the mechanical advantage of the machine.
(iv)the efficiency of the machine.
Answer:
Explanation:
hi
URGENT
A river flows toward 90°. Mark, a riverboat
pilot, heads the boat at 297º and is able to go
straight across the river at 6.0 m/s.
a. What is the velocity of the current?
b. What is the velocity of the boat as seen
from the river bank?
If the boat's speed is s, and the river's speed is r, and the boat is traveling east (0 degrees),
(0,r) + (s cos297,s sin297) = (6,0)
now just solve for r and s.
Pls mark me as brainliest
What's energy band theory???
Answer:
Energy band theory is a basis for describing processes and effects in solid crystals under electromagnetic field impact.
Explanation:
Single atoms have a discrete energy spectrum, which means they can occupy only discrete energy levels. Part of these energy levels are filled with electrons in a non-excited condition. Part of these levels can be occupied only when electrons are excited.
Las carreras de velocidad pura en el atletismo son:
A. Un ladrón perseguido por la policia
B.100 y 200 mts planos
C. salir corriendo cuando la mama lo va a castigar
D.N.A
Help me frfr I don’t understand
The points are
(1,10)
(6,0)
[tex]\boxed{\sf slope(m)=\dfrac{y_2-y_1}{x_2-x_1}}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{0-10}{6-1}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{-10}{5}[/tex]
[tex]\\ \sf\longmapsto m=-2[/tex]
A girl is travelling on her bike at a speed 2.59 m/s. If the
girl and her bike have a kinetic energy of 190 J, what is
the combined mass of the girl and her bike? Show all
your work
Answer:
Mass, m = 146.72 kilograms
Explanation:
Given the following data;
Kinetic energy = 190 J
Velocity = 2.59 m/s
To find the combined mass of the girl and her bike;
Kinetic energy can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;
K.E = ½mv²
Where;
K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
190 = ½*m*2.59
Cross-multiplying, we have:
380 = 2.59m
Mass, m = 380/2.59
Mass, m = 146.72 kilograms
Enlight the contribution of science and technology for current pandemic of Corona virus??
The vaccine ofcourse. They helped in making the vaccine.
Define measurement with examples.
Explanation:
Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. An example of measurement is 15" by 25". ... The dimension, quantity, or capacity determined by measuring.
Measurement refers to the comparison of unknown physical quantity with a known quantity.
for eg. measurement of body while sewing clothes.......
Which is an outer planet?
Answer:
pluto
Explanation:
Dwarf because it is very minut
Answer:
I think Saturn.
Explanation:
I think the inner planets are Mercury, Venus, Earth and Mars whereas the outer ones are Jupiter, Saturn, Uranus and Neptune.
A train 90m long stops in a train station with its front buffers in line with a lamp post on the platform. Later it starts off with an average acceleration of 0.45m/s. What will be its speed in kilometers per hour when the tail buffers pass the lamp post P?
Answer:
The speed of the train when the tail buffers pass the lamp post is 9 m/s
Explanation:
The given parameters are;
The length of the train = 90 m
The initial velocity of the train, u = 0
The average acceleration of the train, a = 0.45 m/s²
When the tail buffer pass the lamp post, P, we have;
The distance travelled, s = The length of the train = 90 m
The kinematic equation of motion is given as follows;
v² = u² + 2·a·s
Where;
v = The speed of the train when the tail buffers pass the lamp post
∴ v² = 0² + 2 × 0.45 m/s² × 90 m = 81 m²/s²
Therefore;
v = √(81 m²/s²) = 9 m/s
The speed of the train when the tail buffers pass the lamp post, v = 9 m/s.
HELP me
Which sentence best describes how the horse is doing work?
A It is using motion to transfer energy and force away from the heavy object
B it is using force to apply power and decrease the energy of the heavy object
C it is using energy to apply the force needed to move the object over a distance
D it is using power to force the heavy object to move over A certain distance
help with this physics question please :)
Answer:
is that rm in you profile pic
A hockey puck has a mass of 0.21 kg. If the hockey puck
is moving with 74 J of kinetic energy, what is its speed?
Show all your work.
Answer:
v = 26.54 m/s
Explanation:
Given that,
The mass of a hockey puck, m = 0.21 kg
The kinetic energy of the hockey puck, E= 74 J
We need to find the speed of the hockey puck. Let the speed is v. We know that, the kinetic energy is given by :
[tex]E=\dfrac{1}{2}mv^2[/tex]
Where
v is the speed
So,
[tex]v=\sqrt{\dfrac{2E}{m}} \\\\v=\sqrt{\dfrac{2\times 74}{0.21}} \\\\v=26.54\ m/s[/tex]
So, the speed of the hockey puck is 26.54 m/s.
you are pedaling forward on your bike. which of the following would decrease your acceleration?
A. A decrease in your mass
B. A increase in your applied force
C. An increase in your mass
D. An increase in your speed
Pedaling forward over the bike with the increase in your applied force would decrease your acceleration. Thus, option B is correct.
What is acceleration?Acceleration is define as the rate at which velocity changes with time, in terms of both speed and direction. The equation for acceleration is:
a=F/m
where, a = acceleration,
F = force applied
m = mass of the object
The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object.
As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.
Therefore, if you are pedaling forward on your bike then a increase in your applied force would decrease your acceleration. Thus, option B is correct.
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Answer:
I just did it. A is right.
Explanation:
state any two effects of gravitational force
Answer:
The effect of gravity extends from each object out into space in all directions, and for an infinite distance. However, the strength of the gravitational force reduces quickly with distance. Humans are never aware of the Sun's gravity pulling them because the pull is so small at the distance between the Earth and Sun.
Answer:
The Earth's gravitational force accelerates objects when they fall. It constantly pulls, and the objects constantly speed up.
Explanation:
on
when you throw a ball
the
ground
and it
bounces back to your hand,
is it elastic collision ? Explain.
Answer:
The ground hits the ball with same force with which the balls hit the ground. That's why ball bounces back.
Gravity stops it from bouncing forever.
Hope this helps..
.
What is the equation for work?
Work = force / distance
Work = force - distance
Work = force + distance
Work = force * distance
Answer:
Work = F X D
Explanation:
Work (J) equals Force (N) multiplied by Distance (M)
numerical filing method is more scientific why give me 4 reason
Answer:
Numerical Methods are mathematical way to solve certain problems.Whether the equations are linear or nonlinear, efficient and robust numerical methods are required to solve the system of algebraic equations.
Analytical solutions are exact solutions based on mathematical principles.
However, the governing partial differential equations of fluid flow are complex and cannot be solved by analytical means. The partial differential equations are therefore converted into a system of algebraic equations that are subsequently solved through numerical methods to provide approximate solutions to the governing equations.
Although we rarely reach on exact answer , we can get really close to the exact answer much quicker than solve analytically.
Answer:
oh my god
Explanation:
how long answer is this
20. A semiconductor is a
crystalline solid that conducts current under any condition
metallic solid that conducts current under any condition
metallic solid that conducts current under certain conditions
crystalline solid that conducts current under certain conditions
Answer:
D. crystalline solid that conducts current under certain conditions
Explanation:
Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.
Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.
