the focal length of david's lens is 50 cmcm . if rebecca stands in front of david at a distance of dodo and david perceives the position of rebecca at didi , what does dodo equal if the magnification is -0.50?
Answers
The distance of dodo is 150 cm.
What is focal length of lens?The distance between a lens's center and its focal point is its focal length. A focal point is a location on the principal axis where, following refraction via the lens, light rays parallel to the principal axis either actually meet or appear to meet.
Given parameters:
the focal length of David's lens is: f = 50 cm.
magnification is: m = -0.50
We have to find: distance of dodo, that is, object's distance : u = ?
We know that:
u =f( 1/m -1)
⇒ u = 50(-1/0.50-1) = - 150 cm.
Hence, distance is 150 cm.
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Related Questions
4 WILL GIVE YOU BRAINLIST
Which sentence supports this claim:A handmade gift is more meaningful than a store-bought gift?
Handmade gifts are usually less expensive than store-bought gifts.
Handmade gifts remind the receiver of the gift not to be so greedy at gift-giving times of the year.
Handmade gifts tend to look less perfect than store-bought gifts.
Handmade gifts require more of the giver’s time and effort than store-bought gifts.
Answers
So the answer is . . .
Handmade gifts require more of the giver’s time and effort than store-bought gifts.
This is the correct answer because putting effort and time into a gift to make it original and one of a kind makes a handmade gift more meaningful than going to the store finding a gift.
Balloon a is ___ charged and balloon c is ___ charged. If balloon a approaches balloon c there will be a force of blank between them
Answers
Balloon A is positively charged, and balloon C is negatively charged. If balloon A approaches balloon C, there will be an electrostatic force of attraction between them.
When two objects carry opposite charges, they exert an attractive force on each other. This force is known as the electrostatic force and follows Coulomb's law. According to Coulomb's law, the magnitude of the electrostatic force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. In this scenario, since balloon A is positively charged and balloon C is negatively charged, they have opposite charges. Therefore, the electrostatic force between them will be attractive. The magnitude of the force depends on the charges of the balloons and the distance between them. It is important to note that without specific information about the charges of the balloons and their distance, it is not possible to determine the exact magnitude of the force. To calculate the force, you would need the values of the charges and the distance between the balloons.
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PLEASE HELP ASAP PHYSICS QUESTION!!
I’LL MAKE YOU BRAINLIEST
What force is acting on the crate once it hits the flat part at the bottom of the ramp? What is the magnitude and direction of that force? (picture included for context)
Answers
Answer:
There will be a force of gravity and a normal force coming from the track itself.
Explanation:
Assuming this is a continuation of an earlier question [20398149], the crate starts at rest and is allowed to slide down the ramp with acceleration a = 2.35 m/s², so the block will have some speed as it reaches the bottom of the ramp and it will continue to slide some distance along the flat part.
If the flat part is made of the same material as the ramp, then in addition to its own weight and the normal force, the crate will also feel some friction that slows down its leftward slide.
• The crate's weight and the normal force act vertically, so that
∑ F = n - w = 0
n = w = mg = (100 kg) (9.8 m/s²) = 980 N
(where ∑ F = net force, n = magnitude of normal force, w = crate weight, m = crate mass, g = mag. of gravitational acceleration)
• The friction acts horizontally, so
∑ F = -f = m a
(where f = mag. of friction and a = crate acceleration)
The surface has a coefficient of kinetic friction of µ = 0.3, so
f = µ n = 0.3 (980 N) = 294 N
So at the bottom of the ramp, there are 3 forces exerted on the crate:
• its weight of 980 N pointing downward
• the normal force of the surface pushing upward on the crate, also of 980 N
• friction of 294 N, pointing to the right
and the two vertical forces cancel each other.
thermal noise is unavoidable and can literally be found everywhere in the universe because it is due to _______ motion of ________ in electrical circuits?
Answers
Thermal noise is the unavoidable noise that occurs due to the thermal motion of particles in electrical circuits.
This type of noise is present everywhere in the universe as it is due to the thermal motion of particles.
This thermal motion is the random movement of particles that is a result of their temperature. At higher temperatures, the particles in a substance have a higher thermal motion, which results in more thermal noise.
The electrical circuit has resistance, and when a current flows through it, the resistance causes collisions between electrons and other atoms. This interaction between the moving electrons and atoms in the conductor produces thermal noise.
Thermal noise is proportional to the temperature of the conductor and is independent of the current or voltage of the signal passing through it. The power of thermal noise is given by the formula P = kTB, where k is Boltzmann's constant, T is the temperature in Kelvin, and B is the bandwidth of the signal.
Hence, it can be deduced that thermal noise is an inevitable occurrence present universally, as it arises from the thermal agitation of particles within electrical circuits. This phenomenon pervades various environments and cannot be eliminated.
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a laser beam is deflected 22.6 degrees by a 30 60 90 prism while passing horizontally through. what is the prism's index of refraction?
Answers
Prism index of refraction is 2.40 if it is deflected by 22.6degrees by a 30-60-90 prism.
Refraction of light is perhaps of the most ordinarily noticed peculiarity, however different waves like sound waves and water waves additionally experience refraction. Refraction makes it feasible for us to have optical instruments, for example, amplifying glasses, focal points and crystals. It is likewise a result of the refraction of light that we can shine light on our retina..
Applying Snell's law at the point of refraction we get
μ₁sinθ₁ = μ₂sinθ₂
where μ₁ is refractive index of the prism,
μ₂ is the refractive index of the air,
sinθ₁ is the angle made by light with prism
and sinθ₂ is the angle made by light beam with air medium.
Now,we know that μ₂=1,θ₁ =22.6°,θ₂=90° - 22.6°=67.4°,μ₁=?
On putting we,get
=>μ₁ ˣ sin(22.6°)= 1 ˣsin(67.4°)
=>μ₁=sin(67.4°)/ sin(22.6°)
=>μ₁=0.923/0.384
=>μ₁=2.403
Hence, prism index of refraction is 2.403.
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how can we deducve the presence and measure the mass of a supermassivce black hole in the center of a galaxy
Answers
Astronomers can study how clusters of stars and gas move around the galactic center in nearby galaxies and use those movements to calculate the mass of the central black hole.
How can we calculate the black hole's mass at the galactic center?By monitoring the star motions in the galaxy's center, Webb will calculate the black hole's mass. Astronomers will calculate the mass of that black hole using NASA's James Webb Space Telescope. The outcome may appear to be unimportant, but a black hole's mass controls how it feeds and interacts with its surroundings.
Black holes are discovered when nearby material, such as gas, is pulled by gravity into a disk around the black hole. The gas molecules in the disk of the black hole are spinning so quickly that they heat up and release X-rays. From Earth, one can observe these X-rays.
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The earplug can reduce the sound level to about 18 decibels (dB). What percentage reduction is this intensity?
Answers
Answer:
1 x 10 -10 whisper at 1m distance.
Explanation:
Properly fitted ear plugs an reduce noise form 15-30db. Although they are better for low frequencyAnswer:
The change in intensity is 63%.
Explanation:
intensity level = 18 db
Let the intensity is I.
Io = 10^(-12) W/m^2
Use the formula of intensity
\(dB = 10 log\left ( \frac{I}{Io} \right )\\\\18 = 10 log\left ( \frac{I}{Io} \right )\\\\1.8 = log\left ( \frac{I}{Io} \right )\\\\\left ( \frac{I}{Io} \right )=63.1\)
So, the change in intensity is 63%.
What is & real world application of an Atwood's Machine? What are some reasons that would account for the percent error calculated above? points)
Answers
An Atwood's machine is an apparatus that consists of two weights suspended over a pulley. It is a simple device used to study the acceleration and tension of a system and has several real-world applications. In general, it is used to measure the effect of gravity on the motion of objects. Some common examples of its use include studying the speed of falling objects and the motion of planets around the sun. It is also used to measure the gravitational pull of the earth and other planets. Atwood's machine is commonly used in physics classes to study the principles of mechanical forces and the laws of motion. It is a simple yet effective way to teach the concept of acceleration and force. It is used to calculate the acceleration of the weights, the force applied to the system, and the tension in the string.
There are several reasons that could account for the percent error calculated above. One reason is that the experiment may have been affected by friction. Friction can cause the weights to move more slowly, which would lead to a lower acceleration. Another reason could be that the weights were not exactly the same mass. This would cause the system to be imbalanced, which would affect the acceleration and tension in the string. Lastly, human error could have also contributed to the percent error. This could include errors in measurement or incorrect calculations.
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Read each scenario and then answer the question. Scenario A: 120 J of work is done in 6 s. Scenario B: 160 J of work is done in 8 s. Scenario C: 200 J of work is done in 10 s. Which scenario uses the most power?.
Answers
The power in every scenario is the same. Power is the measurement of the energy transfer over time.
What is power?Power is the measurement of the energy transfer over time. It can be calculated by the formula,
\(P = \dfrac Wt\)
Where,
\(P\)- power
\(W\) - work
\(t\) - time
In scenario A,
\(P = \dfrac {120 }6 = 20 \rm \ W\)
In scenario B,
\(P = \dfrac {160 }8 = 20 \rm \ W\)
In scenario B,
\(P = \dfrac {200 }{10} = 20 \rm \ W\)
Therefore, the power in every scenario is the same.
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Answer:
Read each scenario and then answer the question.
Scenario A: 120 J of work is done in 6 s.
Scenario B: 160 J of work is done in 8 s.
Scenario C: 200 J of work is done in 10 s.
Four 15 o resistors are connected in a series to a 45-v battery. Draw the circuit (include an ammeter and voltmeter)
Answers
To draw the circuit diagram with four 15 ohm resistors connected in a series to a 45-v battery, along with an ammeter and voltmeter, follow the steps below:Step 1: Place the batteryTo begin with, draw the 45 V battery at the top of the page, as shown in the figure below. Step 2: Add resistorsNext, add the four 15 ohm resistors in a series circuit after the battery, as shown in the figure below.
Step 3: Add the ammeterIn the circuit, an ammeter is placed in series with the resistors to calculate the total current in the circuit. Connect the ammeter between the last resistor and the negative terminal of the battery, as shown in the figure below.Step 4: Add the voltmeter. Finally, a voltmeter is placed in parallel with the resistors to determine the voltage across them.
Connect the voltmeter in parallel with each resistor, as shown in the figure below. [Figure]Hence, this is how the circuit diagram with four 15 ohm resistors connected in a series to a 45-v battery looks like, along with an ammeter and voltmeter.
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9
Fill in the blanks with CONDUCTION, CONVECTION, RADIATION:
is the transfer of energy through direct contact.
is the transfer of energy
through waves
radiation
is the transfer of energy through a medium such as a liquid or a gas.
Answers
Answer:radiation is the transfer energy thru heat waves, conduction is direct contact, and convection is through liquid
Explanation:ik this
A ball is projected upwards from a bridge and hits the ground 5 seconds after it was originally projected its initial velocity is 15 m/s and it’s final velocity is 34 m/s calculate the height of the bridge.Max height = 11.48 m
Answers
Given:
• Time, t =5 seconds
,• Initial velocity, u = 15 m/s
,• Final velocity, v = 34 m/s
Given that the ball is projected upwards from a bridge, let's find the height of the bridge.
Let's first find the height from the top of the bridge to the maximum height.
To find the height apply the formula:
\(v^2=u^2-2as\)Where:
v is the final velocity = 0 m/s (velocity at max height).
u is the initial velocity = 15 m/s
a is acceleration due to gravity = 9.8 m/s²
s is the height.
\(\begin{gathered} 0^2=15^2-2(9.8)s \\ \\ 0=225-19.6s \\ \\ 19.6s=225 \\ \\ s=\frac{225}{19.6} \\ \\ s=11.48\text{ m} \end{gathered}\)The distance from the bridge to the maximum height is 11.48 m.
Now, let's find the maximum height to the ground.
\(v^2=u^2+2as\)Where:
v is the final velocity = 34 m/s
u is the initial velocity = 0 m/s (velocity at the top).
a is acceleration due to gravity = 9.8 m/s²
s is the maximum height.
Thus, we have:
\(\begin{gathered} 34^2=0^2+2(9.8)s \\ \\ 1156=19.6s \\ \\ s=\frac{1156}{19.6} \\ \\ s=58.9\approx59\text{ m} \end{gathered}\)The maximum height is 59 meters.
To find the height of the bridge, we have:
Height of bridge = Maximum height - Distance from top of bridge to max height.
Height of bridge = 59m - 11.48m = 47.52 m
Therefore, the height of the bridge is 47.52 meters.
• ANSWER:
47.52 meters.
A vector points 12.0 units along the x-axis, and 9.00 units along the y-axis.
Find the direction of the vector.
Answers
Answer:
15 units NE
Explanation:
Assuming the coordinate plane is a compass with N being the positive y-axis, we can use the Pythagorean theorem to find the magnitude of the vector. Since the vector is going up by 12 and right by 9 at the same time, it should form a diagonal line, aka the hypotenuse of a triangle. This triangle has both of its leg units as 12, and 9. Pythagorean theorem states that a^2 + b^2 = c^2, that is both of their legs squared is the hypotenuse of the triangle squared. 12^2 + 9^2 = c^2. c = 15. Now that we know the magnitude, let's go back to the quadrants as the compass. Since both units are positive, the vector goes in the positive direction on both sides, which is Quadrant 1. North and East would be the appropriate say for the vector's direction, thus the vector's direction will be 15 units North East.
From which type of clouds do hail pelets form
Answers
Answer:
Cumulonimbus
Explanation:
because Ideal conditions for hail formation are very high clouds with intense updrafts, containing a large quantity of supercooled water (liquid water under 0°C) and with dust particles in the atmosphere.
who said an atom is like a ball with no charge?
Answers
Answer:
Thomson
Explanation:
Thomson in 1904 soon after the discovery of the electron, but before the discovery of the atomic nucleus, the model tried to explain two properties of atoms then known: that electrons are negatively-charged particles and that atoms have no net electric charge.
what is the buoyant force on uncle ned when he is not wearing the helium pants?
Answers
The buoyant force on Uncle Ned when he is not wearing the helium pants is equal to his weight.
The buoyant force on an object is equal to the weight of the fluid displaced by the object. In the case of Uncle Ned, when he is not wearing the helium pants, we can calculate the buoyant force based on his weight and the density of the fluid.
To find the buoyant force, we need to know the density of the fluid and the volume of Uncle Ned's body. Let's assume the density of the fluid is ρ_fluid and the volume of Uncle Ned's body is V_body.
The buoyant force (F_buoyant) can be calculated using the following formula:
F_buoyant = ρ_fluid * g * V_body
where g is the acceleration due to gravity.
Since Uncle Ned is not wearing the helium pants, his weight is balanced by the force of gravity acting on him, so his weight is equal to the buoyant force.
Therefore, the buoyant force on Uncle Ned when he is not wearing the helium pants is equal to his weight.
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The form of energy commonly called light is transferred by
_____ waves
Answers
Answer:
it would be electromagnetic waves
What is the relationship between force and acceleration if the mass of the object is constant?
Answers
sandra is riding a bice at 10.0 meters/second. she slows down to 2.0 meters/second in 10 seconds. her acceleration is blank meters/seconds^2
Answers
Explanation:
\(a = \frac{v - v _{i} }{t} \)
Her intial velocity is 10
Her final velocity is 2
Time is 10 seconds.
\(a = \frac{2 - 10}{10} \)
\(a = - \frac{4}{5} \)
At the center, 6 unmarked red balls are interspersed with 4 blue balls marked with plus signs. A green cloud with 2 concentric white lines surrounds the center, with 2 small green balls marked with minus signs on the inner white line and 2 small green balls marked with minus signs on the outer white line. How many neutrons does this atom have? 4 6 10 14
Answers
Answer:
10
Explanation:
Amu denotes for unified atomic mass.
it is mostly used to define the atom's mass and molecules.
we know that
One unit of amu is 1 ÷ 12 of the mass of a nuclide 12C
And 1 u = 1.660 538 921 × 10-27 kg
In the inside we can found that there is 10 nucleons so here the alss of the atoms would be 10 amu
Answer:
guy above me is right
Explanation:
if the bill is vetoed
Answers
Answer:
Explanation:
A vote is maybe a vote
If you divide a force measured in newtons (1 new-
ton = 1 kg•m/s?) by a speed expressed in meters per
second, in what units will the answer be expressed?
Answers
Someone pls help mee
Answers
plzz help
which causes an object in motion to remain in a motion?
a.gravity
b.velocity
c.friction
d. inertia
Answers
Answer:
Friction is ur ans
Explanation:
Friction is the external force that acts on objects and causes them to slow down when no other external force acts upon them. Inertia is the tendency of a body in motion to remain in motion.
Inertia causes an object in motion to remain in motion as per the law of inertia.
What is motion?Motion is defined as a phenomenon which is described with respect to change in object's position with respect to time.It is given in terms of displacement,velocity,distance ,acceleration,speed.
Branch of physics which deals with motion of objects without any reference to it's cause is called kinematics while the branch which studies forces and their effects on motion is called as dynamics.
Motion applies to various systems like objects,bodies, matter particles ,radiation ,curvature.There are three laws of motion which are proposed by Newton.Classical mechanics is based on Newton's law of motion.Relativistic mechanics is based on modern kinematics.
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most searches of space for evidence of intelligent life concentrate on radio wavelengths because
a. Radio waves can travel long distances without much interference.
b. Radio waves are the most common form of communication.
c. Radio waves are easy to detect and decode.
d. Radio waves carry the most information.
Answers
Most searches of space for evidence of intelligent life concentrate on radio wavelengths because: a. Radio waves can travel long distances without much interference.
Radio waves have the advantage of being able to propagate through space over vast distances with relatively low levels of interference. Unlike other forms of electromagnetic radiation, such as visible light or X-rays, radio waves are not easily absorbed or scattered by cosmic dust, gas, or other intervening objects. This allows radio signals to traverse interstellar distances more effectively, increasing the chances of detecting potential signals from extraterrestrial civilizations.
While it is true that radio waves are commonly used for communication on Earth (option b), this fact alone does not explain why they are preferred for searching for intelligent life in space. Additionally, radio waves are not necessarily the easiest to detect and decode (option c), as that depends on the specific technology and methods employed. Moreover, the statement that radio waves carry the most information (option d) is not necessarily accurate, as information content depends on the complexity and encoding used in a communication system.
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What is the rate which distance changes over time.
Answers
Answer: Speed
Explanation:
Speed is Defined as defined as D/T or distance over time
An animal's response is reinforced in the presence of a tone that is 50 decibels (dB) in loudness, but not a tone that is 70 dB in loudness. In a test of the generalization gradient, the strongest response will likely be to a _____ dB tone.
Answers
On a distance-time graph, time is shown on the y-axis.
A) True
B) False
Answers
Answer:
false : In distance time graph,time is shown on the x -axis
Which of the following rivers flows north in eastern Florida?
St. James
St. Johns
Mississippi
Hudson
Answers
St. John’s
_________
o0o0o0o0o0
a ball is thrown down at 25 m/s from a 500m tall building. how fast is it traveling when it hits the ground?
Answers
Answer:
The speed of the ball when it hits the ground is 102.1 m/s
Explanation:
Given;
initial velocity of ball, u = 25 m/s
distance traveled by the ball = height of the building = h = 500 m
when the ball hits the ground, the final velocity, v = ?
The final velocity of the ball is given by;
v² = u² + 2gh
where;
g is acceleration due to gravity = 9.8 m/s²
v² = (25)² + 2(9.8)(500)
v² = 10425
v = √10425
v = 102.1 m/s
Therefore, the speed of the ball when it hits the ground is 102.1 m/s