Answer:
Rheostat:=> Rheostat is an electric device used as a variable resistance, like the regulator of the fan. It is used to change the electric resistance in the electric circuit.
Principle / Rule:=> Rheostat works on the principle of Ohm’s law. Ohm’s law states that current in a circuit is inversely proportional to the resistance at the given temperature.
[tex] \infty \infty \infty [/tex]
The mass of a baseball is 100 grams and the volume is 25 cm cubed. What is the density?
Answer:20 g/cm.
Explanation:
Answer:4g/cm3.
Explanation: The Density of a substance or object is the mass of the substance per unit volume of the object.
M is mass, =100g
V is volume = 25cm3
Why can't fossils form in igneous rocks Magma flows too quickly for it to settle in The extreme heat destroys all of the remains
Answer:
you are right
Explanation:
You have been offered an admission to a senior high school to persue a programme you like. Write a letter to the headteacher of your former school stating at least two reasons why you are happy with the programme you have been offered in 250 words.
Answer:
Find the letter below.
Explanation:
1237 Richmond Avenue,
Houston, Texas,
U.S.A.
3rd May, 2021.
The Principal,
Carnegie Vanguard High School,
Houston, Texas,
U.S.A.
Dear Sir,
APPRECIATION FOR THE ADMISSION OFFER IN YOUR SCHOOL
I humbly write this letter to express my sincere appreciation for the offer of admission in your highly esteemed institution of learning. The admission letter states that I was admitted to pursue a programme in Computer Science and this is a source of great delight for me. The opportunity is a unique one because I stand a great chance of acquiring deeper knowledge of programming software that will prove invaluable to me in my future career.
Over the years, I have been particularly thrilled with all the inventions that have been made possible with information technology and programming of many useful software. These inventions have made life a lot easier, hence my interest in getting the required knowledge that will enable me to contribute my quota to the society.
This programme will also afford me the opportunity to relate with seasoned professionals in the field of Information Technology. When in contact with these professionals, I hope to ask them several questions on programming, the technicalities involved in it, and what is obtainable in the real-world scenario. Armed with these pieces of information, I believe that the programme will shape me to be an excellent professional that will be useful to the society.
Once again, thank you for this very special opportunity. I hope to fully maximize the privilege.
Yours Sincerely,
Jessica Liam.
7. Telescope efficiency depends on the area of the primary mirror, while angular resolution scales as 1/D, where D is the diameter of the telescope. State which is true concerning the objects observed with a 30m telescope, versus a 10m telescope. A) The 30 m telescope can observe objects 30 times fainter, and with 3 times the resolution of the 10 m telescope. B) The 30 m telescope can observe objects with 1/9 the angular diameter, and 9 times fainter than, the 10 m telescope. C) The 30 m telescope can observe objects 9 times fainter, and with 3 times smaller angular size, than the 10 m telescope. D) The 30 m telescope can observe objects 3 times fainter, and with 3 times smaller angular size, compared to the 10 m telescope.
Answer:
Option C, The 30 m telescope can observe objects 9 times fainter, and with 3 times smaller angular size, than the 10 m telescope.
Explanation:
As we know,
The surface brightness of the object viewed through telescope is proportional to the square of the diameter of the lens
Thus, Brightness ([tex]B_{30}[/tex]) of 30 m telescope would be proportional to [tex]30^2[/tex]
Brightness of 10 m ([tex]B_{10}[/tex]} telescope would be proportional to [tex]10^2[/tex]
Thus, the ration of the two would be
[tex]\frac{B_{30}}{B_{10}} = \frac{30^2}{10^2} \\\frac{B_{30}}{B_{10}} = \frac{9}{1} \\B_{30} = 9 * B_{10}[/tex]
Thus, brightness of 30 m telescope would be able to view 9 times fainter object as compared to the 10 m telescope.
Also , 30 m telescope would be able to view 3 times smaller angular sized object as compared to the 10 m telescope
Hence, option C is correct
During a phase change, such as when an ice cube melts, its temperature —
Answer:
Will start to decrease until it reaches the room temperature where it transforms from solid to liquid as the bonds are weakening and thus water has a low melting point also known as h20
Explanation:
A 74.2 kg teenager slides down a frictionless slide that has an angle of inclination of 38˚. What is the magnitude of the acceleration of the teenager down the slide?
Answer:
Explanation:
This is one-dimensional motion on an incline which makes it so much more funner :/
The equation for this is
w*sinθ - f = ma which is just a fancy version of Newton's second law that says that the sum of the forces acting on an object are equal to that object's mass times its acceleration.
w is the weight of the teen which is also the normal force, [tex]F_n[/tex]. Therefore,
[tex]w=F_n=mg[/tex] where m is mass and g is gravity:
[tex]w=F_n=(74.2)(9.8)[/tex] and we need 2 sig figs for this since there are 2 in 9.8:
w = 730N
Since there is no friction in this problem, the value for f, frictional force, is 0, making our job a bit shorter. Filling in the main equation:
730sin38 - 0 = 74.2a
Since the left side is subtraction and we will eventually have to divide, and the rules for subtraction/addition are different from those for multiplication/division, we will have to subtract first, get the correct number of sig figs for that difference, and then divide, following the rules for division.
730sin38 will have 2 sig figs which is 450. Now
450 - 0 = 74.2a and
450 = 74.2a and divide to 2 sig figs:
a = 6.1 m/s/s
The following diagram shows one positively charged metal egg and one negatively charged metal egg.
What occurs as the eggs come closer to each other without touching?
→ a) The magnitude of the electrostatic force between the eggs increases, and they repel each other.
→ b) The magnitude of the electrostatic force between the eggs decreases, and they repel each other.
→c) The magnitude of the electrostatic force between the eggs decreases, and they attract each other.
→d) The magnitude of the electrostatic force between the eggs increases, and they attract each other.
Answer:
I think the answer is C but I'm probably wrong.
According to Coloum's law, when two charged eggs are brought closer, the magnitude of the electrostatic force between the eggs increases, and they attract each other. Hence, option D is correct.
What is Coloumb's law?Coloumb's law equals the magnitude of charges and distance of charges. It gives force of attraction or repulsion between the charged bodies. Like charges repel each other and unlike charges attract each other.
Coloumb's law states that the force of attraction or repulsion between charged bodies is directly proportional to the product of charges and inversely proportional to the square of distance between them.
The force of attraction or repulsion is given by,F = q₁×q₂ / r². q₁,q₂ is the product of charges and r is the distance of seperation of charges. The force decreases with increase of distance as distance and force are inversely proportional to each other.
From the given, two metal egg is given, one is with positive and other is negatively charged metal egg. When two metal eggs are brought closer, they attract each other as the metal eggs are oppositively charged.
When two oppositvely charged metals are brought closer, the distance of seperation of two metal eggs decreased. When distance of seperation decreases, electrostatic force increases.
Hence, as the metal eggs come closer to each other without touching the distance decreases with increase of electrostatic force and they are unlike charges, thus they attract each other. Hence, the correct option is D.
Learn more about Coloumb's law:
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Which of the following statements best describes a difference between
nuclear fission and nuclear fusion reactions?
Nuclei gain electrons during fission and release electrons during fusion.
Fission generates potential energy, and fusion generates kinetic energy.
С
C
Heavy nucleus split during fission and two light nuclei bind together during
fusion.
O
Fission forms heavier elements, and fusion forms lighter elements.
Answer:
C
Heavy nucleus split during fission and two light nuclei bind together during
fusion.
A drop of oil of volume 10 ^-10 m3 spreads out on water to make a circular film radius 10^-1m what is the thickness of the film
Answer:
The thickness of the film is = 3.183e-9m
Explanation:
It will help us if we understand that the shape of the circular film can be approximated to be a cylinder. The height of this cylinder, or its thickness, in this case, will be very small.
Since we can approximate the shape of the drop of oil to be a cylinder, after it has spread out on the surface of the water, we can use the cylindrical geometric formulas to find out how thick the film is.
The volume of a cylinder = [tex]\pi r^2 h[/tex]
our radius is given as [tex]10^{-1}m = 0.1m[/tex]
the volume is [tex]10 ^{-10} m^3=1e-10m^3[/tex]
Remember that our task is to find the height of the cylinder. We can do this by making the height the subject of the formula.
[tex]h = \frac{Volume}{\pi r^2} = \\\\\frac{1e-10}{\pi \times 0.1^2} = 3.183e-9m[/tex]
Therefore, the thickness of the film is = 3.183e-9m
Think about the mice shown below. Using the space below numbered 1, describe what is happening from figure 1 to 3.
Answer: Natural selection is taking place.
Explanation:
As you can see, the lighter colored mice are more visible than their surroundings, so the hawk picks them off one by one. the brown mice on the other hand are less visible, blending in with their surroundings, so they are successful, and pass on the genes that allow them to survive better.
- anonymous
In the first picture, the mice are in the environment looking for resources necessary for their survival. In the second picture, mice are being hunted by a predator. In the third figure, the rat population decreased as the light rats died and the dark rats survived.
The three figures represent a process called Natural Selection.
What is Natural Selection?It's a biological process.It is a process that causes biological evolution.It is the process that allows the survival of the most adapted individuals to the environment.In the figures, we can see that there is a community of dark and light mice. Dark mice are more adapted to the environment, as they can camouflage themselves more easily.
This camouflage allows the dark mice to evade predators more efficiently. On the other hand, light mice are easily noticed by predators and for this reason, they are quickly devoured.
This causes the number of light mice to decrease to the point where they cease to exist. Meanwhile, the dark mice survive and pass this trait on to their descendants.
More information about natural selection at the link:
https://brainly.com/question/2725702
Define Velocity.
Have a Nice Day Ahead
Answer:
the speed at which something moves in a particular direction
Explanation:
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. ... Velocity is a physical vector quantity; both magnitude and direction are needed to define it.
Suppose a spring compresses by 5cm if you put a 250 gram weight on top of it. How
much potential energy is contained in the compressed spring?
a) 49 J
b) 2.45 J
c) 122 J
d) 0.061 J
e) I cannot tell from the information given.
Answer:
Option D. 0.061 J
Explanation:
We'll begin by converting 5 cm to m. This can be obtained as follow:
100 cm = 1 m
Therefore,
5 cm = 5 cm × 1 m / 100 cm
5 cm = 0.05 m
Next, we shall convert 250 g to Kg. This can be obtained as follow:
1000 g = 1 Kg
Therefore,
250 g = 250 × 1 Kg / 1000
250 g = 0.25 Kg
Next, we shall determine the weight of the object. This can be obtained as follow:
Mass (m) = 0.25 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Weight (W) =?
W = m × g
W = 0.25 × 9.8
W = 2.45 N
Next, we shall determine the spring constant. This can be obtained as follow:
Compression (e) = 0.05 m
Weight = Force (F) = 2.45 N
Spring constant (K) =?
F = Ke
2.45 = K × 0.05
Divide both side by 0.05
K = 2.45 / 0.05
K = 49 N/m
Finally, we shall determine the potential energy contained in the compressed spring. This can be obtained as follow:
Compression (e) = 0.05 m
Spring constant (K) = 49 N/m
Energy (E) =?
E = ½Ke²
E = ½ × 49 × (0.05)²
E = 24.5 × 0.0025
E = 0.061 J
Therefore, the potential energy contained in the compressed spring is 0.061 J
The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about hundreds of thousands of years ago. a million years ago. a hundred years ago. tens of thousands of years ago. a thousand years ago.
Answer: tens of thousands of years ago.
Explanation:
The Sun makes energy by nuclear fusion which is a process by which hydrogen atoms are fused to form helium atoms.
It does this in the core and the process releases a lot of energy that takes quite a long time to get to the surface from said core.
Scientists say that the energy takes between 10,000 and 170,000 years for the energy to escape the core to the surface where it is then radiated to Earth as light.
What Law and explain why.
An airplane turns on its jets to accelerate down a runway.
Answer:Newton's 2nd law
Explanation:Newton's 2nd law also states that the rate at which an object changes speed is proportional to the force that is exerted. Engines provide thrust and accelerate a plane forward along the runway. If the engines supply a small force, only a small acceleration will result.
What are the products(what comes out of) photosynthesis
A. Carbon dioxide , water, sunlight
B. Glucose and carbon dioxide
C. Carbon dioxide water and light energy
D. Glucose and oxygen
Please answer this if you don’t know the answer don’t answer ( dont guess randomly) 11 points
Answer:
D
Explanation:
the 3 products of photosynthesis are glucose (sugar), oxygen and water. D just doesn't include water.
Answer:
It would be C
Explanation:
plants convert carbon dioxide from the air into oxygen.
a cyclist travelling 72 kilometre per hour comes to rest in 5secs
Answer:
14.4
Explanation:
distance / time
so
72/5
14.4
1. Which object is farthest from the origin at t=2sec
A.a B. b
C. they are the same location at t=2sec
D. they are the same distance from the origin , but in opposite direction
2. Which object moves with constant non-zero acceleration
A. A C. both a and b
B. B. D. neither A and B
3. Which object is in its initial position at t=2sec?
A. A C. both a and b
B. B D. neither A and B
Help me ppppppppp
Answer:
that one i know only pe not that sorry again
Please help! I’m so confused and I’m being timed! I will give brainliest!
Answer:
Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. A rocket engine produces thrust through action and reaction. The engine produces hot exhaust gases which flow out of the back of the engine. In reaction, a thrusting force is produced in the opposite reaction.
please help me out i'm so depressed and such a failure
how does the brightness of the lamp (L) vary if we dispalce the cursor (C) of the rheostat
a)Towards A
b) Towards B
Answer:
b mate im pretty sure ig :)
Jack and Jill are pushing a 3 kg object on a rough surface; the object accelerates at a rate of 5 m/s2. Calculate the force applied by the Jack knowing that Jill is pushing 4 N and the rough surface applies 2 N force on the box as friction force.
Answer:
13 N
Explanation:
From the question,
(F₁+F₂)-F' = ma................ Equation 1
Where F₁= Jack's force, F₂ = Jill's force, F' = Friction force, m = mass of the object, a = acceleration of the object.
Given: F₂ = 4 N, F' = 2 N, m = 3 kg, a = 5 m/s²
Substitute these values into equation 1 and solve for F₁
(F₁+4)-2 = 3×5
(F₁+4)-2 = 15
F₁+4 = 15+2
F₁+4 = 17
F₁ = 17-4
F₁ = 13 N
Hence the force applied by Jack is 13 N
A vibrating pendulum makes 20 complete vibrations in 12.2 seconds. Determine the vibrational period of the pendulum, along with the corresponding unit.
Answer:
And the same can be said of a pendulum vibrating about a fixed position or of a guitar ... along the time axis, it is possible to determine the time for one complete cycle. ... It takes 2.3 seconds to complete the first full cycle of vibration. ... Since the standard metric unit of time is the second, frequency has units of cycles/second.
Explanation:
Plz mark brainliest im only 12. and i have never been marked brainliest.
can someone pls help with the last one
Answer:
ummmmmmmmmmmm ask your teacher or perant for help
Explanation:
so umm ask an adult or teen figure and maybe you will get it write not sure do
William took a 7 hour bicycle trip. In all, he traveled 112 miles. What was his average rate of speed in miles per hour?
Answer:
16 miles
Explanation:
112 miles/ 7 hours= 16 miles per hour
In the winter months the number of daylight hours decreases. What accounts for this change?
A. The sun travels faster when the time between sunrise and sunset is shorter
B. The sun is further away when the time between sunrise and sunset is shorter
C. The size of the sun and its revolution around the solar system results in this difference in time
D. The tilt of theEarth and its revolution around the sun results in this difference in time
Answer:
B
Explanation:
The force of gravity between you and Earth is greater than the force of gravity between you and a car because Earth has more __________ than the car.
Answer:Earth has more mass than the car.
in the question
A stereo speaker is made of a flexible cone-shaped material that vibrates, creating a sound wave. A sound wave formed be a speaker travels through air to your ear as a series of compressions and rarefactions of air molecules.
Which statement classifies the sound wave?
transverse wave in which the particles of the wave move in a direction parallel to the wave motion
longitudinal wave in which the particles of the wave move in a direction parallel to the wave motion
transverse wave in which the particles of the wave move in a direction perpendicular to the wave motion
O longitudinal wave in which the particles of the wave move in a direction perpendicular to the wave motion
Answer: longitudinal wave in which the particles of the wave move in a direction parallel to the wave motion
The sound wave is a longitudinal wave in which the particles of the wave move in a direction parallel to the wave motion.
What is a wave of sound?A sound wave can be described as the pattern of distribution caused by the movement of energy that is traveling through a medium, such as air, water, or any liquid or solid matter, etc, as it is traveling away from the source of the sound. There are two types of sound waves:
Longitudinal wave: When the particles of the medium move in a direction parallel to the direction that the wave moves then the wave is known as the longitudinal wave.
Transverse Wave: When the particles of the medium move in a direction perpendicular to the direction that the wave moves then the wave are known as the transverse wave.
As it is given that the sound wave formed by the speaker travels through the air to your ear as a series of compressions and rarefactions of air molecules, therefore, the particles of the medium move in a direction parallel to the direction that the wave.
Hence, the sound wave is a longitudinal wave in which the particles of the wave move in a direction parallel to the wave motion.
Learn more about Sound Wave:
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the device or instrument that transforms light energy to electrical energy
Answer:
Solar panels
sun light into electricity
The motor for your electric car is attached to a generator. The motor has a
resistance of 28 ohms and the current is 3.8 amperes (A). What is the generator's
voltage?
Answer:
106.4V
Explanation:
Voltage = resistance * current
Calculate magnitude and direction of the force between a 1.4 X 10 -3 C charge and a 9.1 X 10 -4 charge when they are separated by 4.8 m.
Answer:
The magnitude and direction of the force between the two charges is 497.66 N in opposite direction.
Explanation:
From the question given above, the following data were obtained:
Charge 1 (q₁) = 1.4×10¯³ C
Charge 2 (q₂) = 9.1×20¯⁴ C
Distance apart (r) = 4.8 m
Force (F) =?
NOTE: Electric constant (K) = 9×10⁹ Nm²/C²
The magnitude of the force between the two charges can be obtained as follow:
F = Kq₁q₂ / r²
F = 9×10⁹ × 1.4×10¯³ × 9.1×20¯⁴ / 4.8²
F = 11466 / 23.04
F = 497.66 N
Thus, the magnitude of the force is 497.66 N.
Since both charges has the same sign (i.e they both positive), the force between them will be a force of repulsion. Hence the force will be in opposite direction.
2. A block of mass 1.2 kg lies on a frictionless surface. A man slides the block
against a spring, compressing it .15m. When the man lets go of the spring, the
block moves at 5 m/s. What is the spring constant of the spring?
mm
.
Answer:
The spring constant will be "1333.33 N/m".
Explanation:
The given values are:
Mass,
m = 1.2 kg
Displacement compression,
x = 0.15 m
Block's velocity,
[tex]v_i=5 \ m/s[/tex]
As we know,
⇒ [tex]E_i=E_f[/tex]
or,
⇒ [tex]K_i+v_i=K_f+v_f[/tex]
⇒ [tex]\frac{1}{2}mv_i^2+0=0+ \frac{1}{2}Kx^2[/tex]
So,
⇒ [tex]K=\frac{mv_i^2}{x_2}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{1.2\times 5\times 5}{0.15\times 0.15}[/tex]
⇒ [tex]=\frac{30}{0.0225}[/tex]
⇒ [tex]=1333.33 \ N/m[/tex]