A sample of 0.500 kg of ice is held at a temperature of 0°C. How much energy
must be added to completely turn the ice into liquid water? (The latent heat of
vaporization for water is 2260 kJ/kg; the latent heat of fusion for water is 333
kJ/kg.)
A. 1130 kJ
B. 666 kJ
C. 167 kJ
D. 4520 kJ
Answer:
C. 167 kJ
Explanation:
The minimum amount of heat require to complete turn the ice into liquid water is equal to the latent heat of the ice, that is, the amount of heat needed by the ice to turn into water. This amount is calculated by:
[tex]Q = m\cdot h_{f}[/tex] (1)
Where:
[tex]m[/tex] - Mass of ice, measured in kilograms.
[tex]h_{f}[/tex] - Latent heat of fusion, measured in kilojoules per kilogram.
[tex]Q[/tex] - Latent heat, measured in kilojoules.
If we know that [tex]m = 0.500\,kg[/tex] and [tex]h_{f} = 333\,\frac{kJ}{kg}[/tex], the latent heat of ice is:
[tex]Q = (0.500\,kg)\cdot \left(333\,\frac{kJ}{kg} \right)[/tex]
[tex]Q = 166.5\,kJ[/tex]
Therefore, the correct answer is C.
Which is an example of current electricity?
1.
In any solution, the part in the greatest quantity or volume is called the ___________.
solute
solvent
2.
The most common type of solution is a ___________-___________ solution.
liquid-solid
liquid-gas
3.
Air is a ___________-____________ solution.
solid-gas
Answer:
1) solvent
2) liquid-solid
3) gas - gas
Explanation:
1) A solution is the homogenous mixture of two or more substances in such a way that its components are uniformly distributed. In any solution, the solvent make up the greatest quantity or volume while the solute is of lesser quantity.
2) liquid-solid is the most common type of solution.
3) A gas solution can be a gas dissolved in a gas, or a liquid dissolved in a gas, or a solid dissolved in a gas. Air is a gas - gas solution, it is composed of oxygen and other dissolved gases in nitrogen
Answer:
B, A, B
Explanation:
had this USA test prep
In downtown Chicago, the east-west blocks are 400 ft long while the north-south blocks are 280 ft long. Because of the many one-way streets, it can be challenging to get around. Veronica starts at the corner of Dearborn and Ohio Streets. She drives four blocks north to Superior, two blocks east to Wabash, then a block south to get to her destination at Wabash and Huron.
Required:
What is the straight-line distance from her starting point?
Answer:
The answer is "1160 ft".
Explanation:
Using the Pythagoras theorem:
[tex]\to a= 280 \times 3= 840\\\\\to b= 400 \times 2= 800\\\\[/tex]
[tex]\bold{\to y^2= a^2+b^2}\\\\[/tex]
[tex]=840^2 +800^2\\\\= 705600+640000\\\\=1345600\\\\=1160 \ ft\\[/tex]
[tex]\to y=1160 \ ft[/tex]
A tire spinning at 5m/s uniformly accelerates to 10 m/s in five seconds. Its radius is 10 cm. Through what angle will pebble stuck in the tire revolve during this interval?
20 cm and 9 cm 30 cm is the distance for 5 mins so it will be 20 cm
I need an expert in physics for help
A toy car rolls down a straight inclined track and its speed increases steadily. At the moment when the car reaches the flat surface at the base of the track, its speed remains constant. Which statement best explains why the speed of the car remains the same when it reaches the flat surface
Answer:
Due to same gravity.
Explanation:
The speed of the car remains the same when it reaches on the flat surface because the gravity is same at every step of flat surface while on the other hand, the speed of car speed increases steadily on the inclined plane due to gravity of the earth. So we can say that speed of the car remains the same on the flat surface due to same gravitational force.
A hockey player is standing on his skates on a frozen pond when an opposing player, moving with a uniform speed of 4.0 m/s, skates by with the puck. After 2.80 s, the first player makes up his mind to chase his opponent. If he accelerates uniformly at 0.14 m/s2, determine each of the following:
a. How long does it take him to catch his opponent?
b. How far has he traveled in that time?
Answer:
a)[tex]t=59.817652833125294s \approx 59.8s[/tex]
b)[tex]D_1=894.01m[/tex]
Explanation:
From the question we are told that
Speed of opposing player [tex]V_2=4.0m/s[/tex]
First player chase his opponent after[tex]t=2.80t[/tex]
Acceleration of first player [tex]a=0.14 m/s2[/tex]
Let time of catch be [tex]t_c[/tex]
a)Generally the Equation for distance covered is mathematically given as follows
Distance to catch First opponent
[tex]D_1=\frac{1}{2}(0.14)t^2[/tex]
[tex]D_1=0.07t^2[/tex]
Distance to covered Second opponent
[tex]D_2=(2.8+t)*4[/tex]
Generally when first opponent catch the second opponent it is represented mathematically as
[tex]D_2=D_1[/tex]
[tex]0.07t^2=(2.8+t)*4[/tex]
[tex]0.07t^2=11.2+4t[/tex]
[tex]0.07t^2-4t-11.2[/tex]
[tex]t=59.817652833125294s \approx 59.8s[/tex]
b)Generally the the total time traveled by the first opponent is mathematically given as
[tex]D_1=\frac{t^2}{4}[/tex]
[tex]D_1=\frac{59.8^2}{4}[/tex]
[tex]D_1=894.01m[/tex]
The net force on the propeller of a 3.2 kg model airplane is 7.0N forward. What is the acceleration of the airplane? If it starts from rest, what is the velocity of the plane after 2.5 seconds?
Answers:
Acceleration = 2.1875 m/s^2
Velocity after 2.5 seconds = 5.46875 m/s
=======================================================
Work Shown:
Part 1
The mass is m = 3.2 and the force is F = 7.0
Apply the formula F = ma to find the acceleration to be...
F = ma
7.0 = 3.2*a
7.0/3.2 = a
2.1875 = a
a = 2.1875
The acceleration is 2.1875 m/s^2
Every second, the velocity of the plane is increasing by 2.1875 m/s.
----------------------
Part 2
We have the following variables
vi = initial velocity = 0 m/s (since it starts from rest)vf = unknown final velocity (what we're trying to figure out)t = change in time = 2.5 secondsa = acceleration = 2.1875 m/s^2Using one of the kinematics equations, we can then say,
vf = vi + a*t
vf = 0 + 2.1875*2.5
vf = 5.46875
After 2.5 seconds, the airplane is traveling 5.46875 m/s.
5.46875 m/s converts to roughly 12.2332 mph.
Define joule conversion factor?
Explanation:
Joule, unit of work or energy in the International System of Units (SI); it is equal to the work done by a force of one newton acting through one metre. ... In electrical terms, the joule equals one watt-second—i.e., the energy released in one second by a current of one ampere through a resistance of one ohm.
PLEASE HELP!!!! What are 3 ways that machines can make doing work easier? (thats the whole question)
Answer:
Machines reduce the time of work hence reducing the rate of doing work ( power ).
Machines e.g pulleys carry heavy loads with a less and reasonable effort.
Machines e.g generators induce current in a limited amount of time
Answer:
they can do work easier for an example a car a car make things easier by going some were far it can also be used to help people travel instead of a plane it can also be used for carriying things like a boat. (you can put it in a diffrent way)
Explanation:
hope it helps! :)
3.7. A dog searching for a bone walks 3.50 m south, then 8.20 m at an angle 23.1 degrees north of east, and finally 15.0 m west. (a) What is the magnitude of the dog’s total displacement? (b) What is the direction of the dog’s total displacement where directly east is taken as zero degrees and counter-clockwise is positive?
Answer:
Explanation:
We shall represent displacement of dog in vector form , in terms of i , j , i representing east and j representing north .
Dog travels 3.5 m south .
Displacement D₁ = - 3.5 j
then dog travels 8.2 m , 23.1 degree north of east
Displacement D₂ = 8.2 cos23.1 i + 8.2 sin23 j
D₂ = 8.2 cos23.1 i + 8.2 sin23.1 j
= 7.54 i + 3.22 j
Third displacement
D₃ = - 15i
Total displacement = D₁ + D₂ + D₃
= - 3.5 j + 7.54 i + 3.22 j -15i
= - 7.46 i - 0.28 j
Magnitude of displacement = √ ( 7.46² + .28²)
= √(55.65 + .08 )
= 7.46 m
b ) Direction of displacement
If Ф be angle , displacement makes with west direction
TanФ = .08 / 55.65 = .00143
Ф = .082 degree south of west or almost west .
From east , this angle = 180 + .082 = 180.082 , counterclockwise .
pls explain why
two cars start a trip of 200 km at the same time. the first car travels at 90 km/h and the second at 110 km/h. how much more time in minutes does it take for the slower car to reach its destination?
Answer:
5
Explanation:
give thanks pls
The moment of inertia of a lever is 50 kg m^2 with a mass of 2 kg. What is the
radius?
Answer:
huh
Explanation:
A flower vase is sitting on a shelf when a gust of wind from an open
window blows it down. If the vase has a mass of 0.6 kg and the shelf is 1.5
m off the ground, what is the gravitational potential energy of the vase
before it falls?
Answer:
8.82 J
Explanation:
Recall that gravitational potential energy is defined as:
U = m * g * h
Then in our case, the gravitational potential energy U would be:
U = 0.6 * 9.8 * 1.5 J = 8.82 J
Which of the following is a pure substance?
Heredity is best described as th-
Explanation:
The most established layers are on the base, and the most youthful layers are on the top. Since dregs here and there incorporate once-living creatures, sedimentary stone regularly contains a great deal of fossils. Fossils are once living beings that have been transformed into rock, fit as a fiddle or type of the creature can in any case be seen.
In part C of the lab, when two wires are in parallel, so that the current flows in the same direction inside them, the directions of the magnetic fields in the region between the two wires are
Answer:
the magnetic field between the two wires is zero
Explanation:
given wire the magnetic field is circular with the direction given by the fingers of the right hand.
As the two wires have the same direction of the current, the fields are circular rotating in an anticlockwise direction, therefore in the region between the two wires each field has the opposite direction of movement and they cancel out.
In summary the magnetic field between the two wires is zero
An asteroid with a mass of 3.5x10kg is 26,000m from a second asteroid with a
mass of 3.0x1012 kg.
Calculate the gravitational force between the two asteroids.
Answer:
F₁₋₂ = 1.036*10⁻⁵ [N]
Explanation:
In order to solve this problem, we must use the law of universal gravitation, which can be defined by means of the following expression.
[tex]F_{1-2}=G*\frac{m_{1}*m_{2}}{d^{2} }[/tex]
where:
F₁₋₂ = Force among the two bodies [N]
G = Universal gravity constant = 6.67 *10⁻¹¹ [N*m²/kg²]
m₁ = mass of the first body = 3.5*10 [kg]
m₂ = mass of the second body = 3*10¹² [kg]
d = separation distance = 26000 [m]
Now replacing:
[tex]F_{1-2}=6.67*10^{-11}*\frac{3.5*10*3*10^{12} }{26000^{2} } \\F_{1-2}=1.036*10^{-5}[N][/tex]
An object on the end of a spring with spring constant k moves in simple harmonic motion with amplitude A and frequency f. Which of the following is a possible expression for the kinetic energy of the object as a function of time t?
a. kA^2sin^(2πft)
b. 1/2kA^2cos^2(2πft)
c. 1/2kA sin(2πft)
d. kAcos(2πft)
e. 1/2kAsin(2πft)
The expression for the kinetic energy of the object as a function of time, t is [tex]K.E = \frac{1}{2} k A^2 \ cos^2 \ (2\pi ft)[/tex].
The general wave equation is given as;
[tex]x = A \ cso(\omega t)\\\\x = A \ cos(2 \pi ft)[/tex]
Apply the principle of conservation of energy, the kinetic energy of a particle in such motion is given as;
[tex]K.E = U_x\\\\K.E = \frac{1}{2} kx^2[/tex]
Substitute the value of x into the kinetic energy equation
[tex]K.E = \frac{1}{2} kx^2\\\\K.E = \frac{1}{2} k ( A \ cos (2\pi ft)^2\\\\K.E = \frac{1}{2} k A^2 \ cos^2 \ (2\pi ft)[/tex]
Thus, the expression for the kinetic energy of the object as a function of time, t is [tex]K.E = \frac{1}{2} k A^2 \ cos^2 \ (2\pi ft)[/tex].
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What are two ways electromagnetic waves are used in a home computer scanner?
A.
An image is produced when a silicon chip releases electrons by the photoelectric effect.
B.
Visible light is reflected off an object and then captured by a charge-coupled device.
C.
X-rays shine on objects, and the rays either pass through or are absorbed by the objects.
D.
Red light shines on a black-and-white object, and light is reflected according to the pattern of black and white.
Two ways electromagnetic waves are used in a home computer scanner are:
An image is produced when a silicon chip releases electrons by the photoelectric effect.Visible light is reflected off an object and then captured by a charge-coupled device.What is electromagnetic wave?In terms of science, electromagnetic radiation (EMR) is made up of electromagnetic (EM) field waves that travel over space while carrying electromagnetic radiant energy. It consists of X-rays, gamma rays, microwaves, infrared, visible light, ultraviolet, and radio waves. These waves are all a component of the electromagnetic spectrum.
Electromagnetic waves, which are synchronised oscillations of the electric and magnetic fields, are the traditional form of electromagnetic radiation. The electromagnetic spectrum is created at various wavelengths depending on the oscillation frequency. Electromagnetic waves move at the speed of light in a vacuum.
Hence, option (A) and (B) are correct.
Learn more about electromagnetic wave here:
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The total amount of force exerted on an object is called
Balanced
Unbalanced
Force
Net Force
Answer:
net force
Explanation:
net force is the total amount of force exerted on an object.
What happens to the molecules of a substance when it changes phase?
When it comes to phase shifts or phase change the greater the intermolecular interactions are the closer the molecules are to one another.
What is phase change?A phase change occurs when matter transitions from one state to another (solid, liquid, gas, plasma). When enough energy is provided to the system (or when a significant quantity is removed), as well as when the pressure on the system is adjusted, these changes occur.Any two phases of matter can undergo phase transitions.All phase shifts are accompanied by an energy shift.Isothermal phase shifts occur in all cases.Temperature changes can cause substances to change phase often. Most substances are solid at low temperatures; as the temperature rises, they become liquid; and at even higher temperatures, they become gaseous.To Know more about Phase change here
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importance of choke coil?
Answer:The choke coil works because it can act as an inductor. When the current pass through will change as AC currents creates a magnetic field in the coil that works against that current. This is known as inductance and blocks most of the AC current from passing through.
Explanation:
Question 3 of 10
An engine performs 6400 J of work on a motorbike. The motorbike and rider
have a combined mass of 200 kg. If the bike started at rest, what is the speed
of the bike after the work is performed?
Answer:
8 m/s
Explanation:
KE Formula: KE = 1/2mv^2
Kinetic Energy is equal to energy, J.
6400 = 1/2 * 200 * V^2
1/2 * 200 = 100
6400 = 100 * V^2
6400/100 = V^2
64 = V^2
Square root both sides
Speed is 8 m/s
1) Should I take vitamin D supplements in the winter?
A man rides a bicycle that is connected to an electrical generator. If he rides as hard as he can, his body can produce a mechanical power of 500 W, but the generator is only 40% efficient at converting mechanical energy into electrical energy.How many 100 W incandescent light bulbs can he power
Answer: the man can power 2 incandescent light bulbs
Explanation:
Given that;
power produced by the body while riding = 500 W
Efficiency of generator = 40% = 0.4
First we need to convert the mechanical energy to electric energy;
which efficiency of generator multiply by power input, so
⇒ 0.4 × 500 = 200 W
Now, if 1 incandescent light bulbs is 100 W
x incandescent light bulbs bulbs is 200 W
100x W= 200 W
x = 200 W / 100 W
x = 2
Therefore, the man can power 2 incandescent light bulbs
Two cars, initially at rest and 5 km apart at t=0 , simultaneously move toward each other. Car A travels at a constant speed of 55 km/hour, while car B travels at a constant speed of 12 km/hour. How long will it take care from t=0 for car A to meet car B?
Select one:
a. 24.5 s
b. 490 s
c. 245 s
d. 268 s
e. None of the above.
Answer:
d. 268 s
Explanation:
Constant Speed Motion
An object is said to travel at constant speed if the ratio of the distance traveled by the time taken is constant.
Expressed in a simple equation, we have:
[tex]\displaystyle v=\frac{d}{t}[/tex]
Where
v = Speed of the object
d = Distance traveled
t = Time taken to travel d.
From the equation above, we can solve for d:
d = v . t
And we can also solve it for t:
[tex]\displaystyle t=\frac{d}{v}[/tex]
Two cars are initially separated by 5 km are approaching each other at relative speeds of 55 km/h and 12 km/h respectively. The total speed at which they are approaching is 55+12 = 67 km/h.
The time it will take for them to meet is:
[tex]\displaystyle t=\frac{5}{67}[/tex]
t = 0.0746 hours
Converting to seconds: 0.0746*3600 = 268.56
The closest answer is d. 268 s
A prospector finds himself holding his bag of gold and standing in the middle of a large pond of frictionless ice. Use the Law of Conservation of Momentum to explain how he can get to the side before he freezes
Answer:
Explanation:
He can not walk on the ice because ice is frictionless . But he can move to shore or side using law of conservation of momentum . He will throw the bag of gold towards the side opposite to shore . This will create a motion in himself in opposite direction according to law of conservation of momentum.
Let m and M be mass of bag and prospector , v and V be velocity created in bag and prospector after throw of bag . Initially , both bag and prospector were at rest so initial momentum = 0 . Final momentum of both = mv - MV .
negative sign is due to their opposite motion .
According to law of conservation of momentum
MV - mv = 0
MV = mv
In this way he can create motion in himself to move to side .
The coefficient of friction on a surface is 0.25. A box requires 100N to slide it across the surface. What is the weight of the box?
