Explanation:
We know that,
Magnitude of a unit vector is 1.
and, magnitude of a vector in the form [tex] \sf a \hat{i}+b \hat{j} + c \hat{k} [/tex]
is [tex] \sf \sqrt{a^2+b^2+c^2 } [/tex]
The given vector is,
[tex]\sf \vec{A}= 0.3 \hat{i} + 0.4 \hat{j} + B \hat{k}[/tex]
Magnitude of the given vector is,
[tex]\sf | \vec{A}|= \sqrt{(0.3)^2+(0.4)^2+B^2} =1[/tex]
[tex]\sf \sqrt{0.09+0.16+B^2}=1[/tex]
[tex]\sf 0.25+B^2=1[/tex]
[tex]\sf B^2=1-0.25=0.75[/tex]
[tex]\sf B = \sqrt{0.75} ≈ 0.87[/tex]
Calculate how many half-lives are required for a number of radio-active nuclei to decrease to one-millionth of
the initial number.
Answer:
it would depend on which element u would be considering
Explanation:
as helium , oxygen , carbon ,sodium and other would be easier while plutonium , americium and other very radioactive elements would be harder
Answer:
~ 20 half lives
Explanation:
(1/2) ^n = 1/1,000,000 n = number of half-lives
LOG both sides to get
n LOG 1/2 = -6
n = -6/(LOG (1/2)) = 19.931 or approx 20 half lives
Purpose: Determine the kinetic energy of a constant velocity car when it is switched on.
A. Design an experimental procedure to find the kinetic energy of a constant velocity car. Make a list of the equipment you would use.
B. Describe the overall procedure you would follow. Provide enough detail so another student could replicate the experiment, including any steps necessary to reduce experimental uncertainty.
C. Clearly list what data you need to collect.
D. List what equations you need to use with the data you collected to find the kinetic energy of the car.
E. Describe the energy conversion that occurs while the constant velocity car is running. What other types of energy does the car have, aside from kinetic energy?
F. If you were to actually complete this lab, what are some potential sources of error that could cause your answer to be incorrect?
Answer:
The kinetic energy is proportional to the square of the speed, so doubling the speed increases the kinetic energy by a factor of 4.
A car starts from rest and reaches a velocity of 50.0 m/s in 41.0 seconds. What is the
acceleration
Please show how you got it
Answer:
1.21 or 1.2 acceleration
Explanation:
i think it is 50.0/41.0
which would equal 1.21(depending on if you round it)
Why is friction useful between your feet and the ground?
Answer:
It allows you to walk faster.
Explanation:
It is the same force that allows you to accelerate forward when you run. Your planted foot can grip the ground and push backward, which causes the ground to push forward on your foot. We call this grip type of friction, where the surfaces are prevented from slipping across each other, a static frictional force.
A duck has a mass of 2.70 kg. As the duck paddles, a force of 0.110 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.220 N in a direction of 47.0° south of east. When these forces begin to act, the velocity of the duck is 0.120 m/s in a direction due east. Find (a) the magnitude and (b) the direction (relative to due east) of the displacement that the duck undergoes in 2.70 s while the forces are acting. (Note that the angle will be negative in the south of east direction.)
a) The magnitude will be 0.838m
b) The displacement will be -17.35°
What is displacement?The path covered by an object from its initial point to final point.
Forces acting on the duck
x-axis: 0.13 + 0.16*cos(-56°) = 2.7 * ax
ax = 0.0813 m/s^2
y-axis: 0.13*sin(-56°) = 2.7 * ay
ay = -0.0491 m/s^2
The displacement on the x-axis
X = Vox * t + ax/2 * t²
X = 0.12* 3.2 + 0.0813/2*3.2²
X = 0.8
The displacement on the y-axis:
Y = Voy * t + ay/2 * t²
X = 0 - 0.0491/2*3.2²
Y=-0.25m
So, the magnitude and angle of this displacement [0.8,-0.25] is:
0.838m at an angle of -17.35°
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Suppose an astronaut has landed on Planet * Fully equipped, the astronaut has a
mass of 120 kg and when the astronaut gets on a scale, the reading is 46 N. what is
the acceleration due to gravity on Planet X. (Answer to 2 decimal places) you
From the calculations, the value of the acceleration due to gravity is 0.38 m/s^2.
What is weight?The weight of an object is obtained as the product of the mass of the body and the acceleration due to gravity.
Thus;
When;
mass = 120 kg
weight = 46 N
acceleration due to gravity = 46 N/120 kg
=0.38 m/s^2
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8. How do you think that might be the reason why the Sun warms more in the summer? To give your explanation can rely on the angle of the sunlight falling in the months: January, March and June.
Answer:
Because the angle of the sun moves/rotates in the summer, the sun's rays move their angle and impact the earth.
in your own words, explain what friction is
Answer:
Friction is the resistance of motion when two objects rub against each other.
Explanation:
Hope this helps.
Calculate the current through the ammeter (look at photo)
Answer:
6 amps
Explanation:by Kirchhoff's loop rule the current at any point in the loop must be equal or charge would be building up. The current at the ammeter is equally to the total current through the sun of the paths in parallel which it is in series with
What is the average translational kinetic energy of nitrogen molecules at 1600 K? A. 1.31x10-20 J. B. 2.31x10-20 J. C. 3.31x10-20 J. D. 4.31x10-20 J.
KE
5/2KTFor nitrogen n=5
So
5/2(1.38×10^{-23})(1600)5500×10^{-23}5.5×10^{-20}Jwhich two forces operate over only very SHORT distances?
A. weak nuclear and gravitational
B. strong nuclear and gravitational
C. weak nuclear and electromagnetic
D. strong nuclear and weak nuclear
Strong nuclear and weak nuclear forces act only over short range distances.
What are forces?Forces are agents which bring about a change in the state or motion of an object.
Forces can be described as pull or push agents.
Forces can either be contact or non-contact forces.
Some non-contact forces are gravitational forces and nuclear forces.
Nuclear forces act only over short range distances. Example are the strong and weak nuclear forces.
Therefore, strong nuclear and weak nuclear forces act only over short range distances.
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Kinetic energy is energy that is stored and not moving
O True
O False
when a metal sphere is dropped in to a tall cylinder containing liquid its acceleration is g÷2 (gravity over 2) show that : density of metal =2density of liquid
The density of the metal sphere is 2 times the density of the liquid as proved.
Net upward force acting on the metal sphereThe net upward force acting on the sphere as it is dropped into the liquid is calculated as follows;
F = σVg - ρVg
ma = σVg - ρVg
where;
ρ is density of the liquidσ is the density of the metala is acceleration of the metalσV(a) = σVg - ρVg
σ(a) = σg - ρg
σ(g/2) = σg - ρg
g(σ/2) = g(σ - ρ)
σ/2 = σ - ρ
σ/2 - σ = - ρ
-σ/2 = - ρ
σ = 2ρ
Thus, the density of the metal sphere is 2 times the density of the liquid as proved.
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1. Los Angeles lies on Pacific plate, San Francisco lies on North American plate. When will the two cities meet if the distance between them is 600 km and Pacific plate is moving (NW) at 5 cm/yr?
Los Angeles lies on the Pacific plate, San Francisco lies on the North American plate, and the meeting point of the two cities is mathematically given as
T = 120 x 105 years
What is the meeting point of the two plates?Generally, the equation for Distance is mathematically given as
D = Rate x Time
Therefore
T = D/R
T = (600 x 105) / 5
T = 120 x 105 years
In conclusion, the meeting point of the two plates will be
T = 120 x 105 years
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Calculate the density of the baseball. Use the formula
D = m/V
where D is the density, m is the mass, and V is the volume.
Determine whether the density of baseball is within the legitimate range for an official baseball.
Record your answers in Table C of your Student Guide.
What is the density of the baseball?
1.38
g/cm3
The acceptable density range of official baseballs is between 0.70 g/cm3 and 0.80 g/cm3. Is the questionable ball in this range of acceptable density?
If the density of the baseball is within the acceptable density range of 0.70 g/cm³ and 0.80 g/cm³, then your response would be Yes and vice-versa.
What is density?Density can be defined as a ratio of mass to the volume of an object such as a baseball. Mathematically, the density of a baseball can be calculated by using this formula:
Density = Mass/Volume
Since the necessary parameters weren't provided in the question, I would give an insight on how to answer the question. You should substitute the mass and volume of the given baseball into the above formula and then solve.
Furthermore, if the density of the baseball is within the acceptable density range of 0.70 g/cm³ and 0.80 g/cm³, then your response would be Yes. However, if the density of the baseball is above or below the acceptable density range, then your response would be No.
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Identrying the speed of the Cart
Complete the statements using data from Table A of your Student Guide.
cm/s.
The speed of the cart after 3 seconds of Low fan speed is
The speed of the cart after 5 seconds of Medium fan speed is
The speed of the cart after 2 seconds of High fan speed is
cm/s.
cm/s.
The speed of the cart after 3 seconds of Low fan speed is equal to 54 cm/s.
How to calculate the speed?Mathematically, speed can be calculated by using this formula;
Speed = distance/time
At Low fan speed after 3 seconds, the distance covered is 162 cm:
Speed = 162/3
Speed = 54 cm/s.
At Medium fan speed after 5 seconds, the distance covered is 600 cm:
Speed = 600/5
Speed = 120 cm/s.
At High fan speed after 2 seconds, the distance covered is 128 cm:
Speed = 128/2
Speed = 64 cm/s.
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The speed of the cart after 3 seconds of Low fan speed is 55 cm/s.
The speed of the cart after 5 seconds of Medium fan speed is 120 cm/s.
The speed of the cart after 2 seconds of High fan speed is 63 cm/s.
What is speed?
Speed is defined as the rate of change of the distance or the height attained. it is a time-based quantity. it is denoted by u for the initial speed while v for the final speed. its si unit is m/sec.
The graph in the attachment may be used to estimate the cart speed for various fan speeds.
Blue letters indicate the low fan speed. When the line drawn from x hits the blue line, the elapsed time is indicated on the x-axis cart speed after three seconds.
This is equivalent to 55 cm/s.Yellow markings indicate the medium fan speed. After 5 seconds, the line drawn from the point marked 5 on the x-axis crosses the yellow line, marking the time that has passed.
The intersection of the yellow line with the line drawn from the point marked 5 on the x-axis indicates the cart speed five seconds later. The y-axis measurement is roughly 120 cm/s.
Green markings indicate the high fan speed. On the x-axis is the elapsed time. Cart speed at the place where the green line and the line drawn from the x-point axis 2 connect. The y-axis reading is roughly 63 cm/s.
Hence, after the specified seconds, the cart's estimated speeds at low, medium, and high speeds are 55 cm/s, 120 cm/s, and 63 cm/s, respectively.
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How is gravity involved in the formation of stars?
Group of answer choices
Causes a black dwarf to get dense enough for fusion to happen
Causes nuclear fusion, speeding up the atoms in the nebula
Causes nuclear fusion, slowing down the atoms in the nebula
Gravity causes a swirling nebula to contract into a ball
Gravity causes a black dwarf to get dense enough for fusion to happen.
How is gravity involved in the formation of stars?Gravity compresses the core of a protostar which leads to the increase in temperature. When the temperature is high enough that the star starts fusing hydrogen into helium. This fusion reaction is responsible for the formation of new stars.
So we can conclude that Gravity causes a black dwarf to get dense enough for fusion to happen.
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What do Base Isolators act like on
earthquake resistant buildings?
A. suspension cables
B. rotating pistons
C. levers
D. shock absorbers
Einstein published three major scientific papers. One of these put forward a new way of calculating the size of molecules. Another explained Brownian motion — the random dance performed by specks of dust trapped in a fluid. Einstein suggested that the tiny particles making up the fluid — its atoms or molecules — were bouncing against the specks of dust and causing the motion. These papers helped to establish the reality of atoms and molecules. Another of Einstein’s 1905 papers explained the photoelectric effect — the way that metals could emit electrons (tiny charged particles) from their surface when light was shone on them. Most scientists believed that light travelled in waves — like sound or water waves. But Einstein suggested that the photoelectric effect could be explained if light could also behave as a stream of tiny packets of energy.
(2) Einstein’s paper on the photoelectric effect helped give birth to quantum theory, and it was for this paper that Einstein received the Nobel Prize in 1922. Quantum theory led, in the 1920s and 1930s, to another revolution in physics. Physicists showed that, as well as light waves behaving like particles, particles could sometimes act as waves. This theory established “objective probability” in physics. This was the idea that completely unpredictable chance events can take place at the subatomic level. Einstein never fully accepted the prevalent interpretation of quantum theory. But, while many of these interpretations involve wild metaphysical flights of fancy, the physical results are, like those of relativity, very well established.
(3) Marrying together the two pillars of 20th century physics — relativity and quantum theory — is a central problem for physics even today. Successfully doing this may require a revolution in science similar to those begun by Newton and Einstein. There are three main interconnected driving forces for such changes in science. The first is the development of technology. Changes in technology can make new experiments possible and they also influence the problems that scientists develop an interest in. Newton was fascinated by the new machines of the 17th century. Similarly, Einstein was fascinated by electricity and magnetism. This influence also works in a negative way. The governments and multinationals that control technology are often able to dictate what is researched.
(4) The second factor driving scientific progress is the way that the dominant ideas in society change. Ideas from the broader culture can impinge upon science. Newton’s ideas were part of a revolutionary new attempt at a rational explanation of both nature and society. On the other hand, the dominant ideas in society can also limit the development of science. This is most obvious in the social sciences, where delving too deeply into how society is organized might raise difficult questions for our rulers. Less is at stake in the natural sciences. Indeed, improvements in natural sciences are vital to our rulers if they want to compete effectively with each other. But the distorted worldview of capitalism still impacts on science. Extremely narrow and specialized bodies of knowledge develop—creating problems for scientists trying to bring about the kind of sweeping revolution heralded by Einstein.
(5) Finally, science moves forward because scientists seek to develop logically consistent theories. This can push them beyond the dominant or common sense ideas of their time. Einstein’s breakthrough cannot be reduced simply to changes in technology or wider cultural and ideological shifts. Science is not simply the gathering and ordering of data about the outside world. It also requires abstraction—developing theories about the underlying laws of nature that are usually not immediately apparent. This crucial role of theory is not just a feature of the natural sciences.
(6) Einstein argued that “common sense is the prejudices acquired by age 18”. Marxist theory, which is a social science topic, challenges “common sense” political ideas. If we, according to this theory, want to change the world, we need to combine our actions with theory that digs below the surface appearance of society to understand how the system works.
What is the main issue being discussed?
The main issue that is being discussed in the manuscript is the development of science.
What factors affect development of science?Capitalism impacts on science because extremely narrow and specialized bodies of knowledge creating problems for scientists to bring revolution. The dominant ideas in the society can also limit the development of science.
So we can conclude that the main issue that is being discussed in the manuscript is the development of science.
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06.** A block takes twice as long to slide down an inclined plane that makes an angle of 35 with the horizontal as it does to fall freely through the same vertical distance h. What is the coefficient of kinetic friction? [μ = 0.16]
The coefficient of kinetic friction between the block and the incline is 0.168.
Coefficient of kinetic frictionThe coefficient of kinetic friction is determined from the principle of conservation of energy as follows;
distance traveled on the incline = L
L = h/sin35
L = 1.743 h
Since it takes twice the time travel down,
velocity to slide = 1.743 h/2t = 0.871 v
v is the velocity to drop from the vertical heightK.E of the block when it slides = ¹/₂mv₁² = ¹/₂m(0.871v)² = 0.871²(K.E to fall) = 0.758K.E to fall straight down
Energy lost to friction1 - 0.758 = 0.24
Conservation of energyμmgcos(35) = 0.24(mgsin(35)
μcos(35) = 0.24(sin(35)
μ = 0.168
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Discuss how wind energy was used in ancient times.
Answer:
People used wind energy to propel boats along the Nile River as early as 5,000 BC. By 200 BC, simple wind-powered water pumps were used in China, and windmills with woven-reed blades were grinding grain in Persia and the Middle East.
Explanation:
Hope it helps you:)))))
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Write the laws of refraction.(It should be Snell's law)
Explanation:
Snell's Law of refraction:
Refraction of light obeys the following its two laws which's snell's law.
The incident ray, the normal at the point of incidence and the refracted ray, all lie in the same plane. For a given pair of media and given colour of light, the ratio of the sine of angle of incidence i to the sine of angle of refraction r is a constant i.e.[tex] \rm \cfrac{sin \: i}{sin \: r } = \mu[/tex]
This is known as the refractive index of the second medium with respect to the first medium. Mu is given as:
[tex] \rm\mu = \cfrac{Speed \; of \; light \; in\; the\; first \; medium}{Speed \; of \; light \; in\; the\; second \; medium}[/tex]
Let's take an example.
If a ray light travels from air to water,then mu = sin i/sin r is the refractive index of water with air.
[tex]\rm \cfrac{sin \: i}{sin \: r } = \mu[/tex]
Ex.1:Ray light from air to water
sin i = 3*10^6 m/s^1sin r = 2.25*10^8 m s^-1[tex] \rm \mu \: = \cfrac{3 \times {10}^{8} \: m \: s {}^{1} }{2.25 \times 10 {}^{8} \: m \: s {}^{ - 1} } = \cfrac{4}{3} = \boxed{ 1.33}[/tex]
Ex.2: Ray light from Air to glass:
sin i = 3*10^8 m s ^-1sin r = 2*10^8 m s^-1[tex] \rm \mu \: = \cfrac{3 \times {10}^{8} m \: s {}^{ - 1} }{2 \times {10}^{8 \: } m \: s {}^{ - 1} } = \cfrac{3}{2} = \boxed {1.5}[/tex]
[tex] \rule{225pt}{2pt}[/tex]
PLS HELP A magnetic field is formed when
a. the spin of the electrons is
aligned.
b.protons in a material all spin in
the opposite direction.
c. the north and south poles align.
d. a permanent magnet is dropped.
Answer:
proton in a material all spin in the opposite direction
Which shows the correct order of processes leading up to the formation of a main sequence star?
(A Gases condense to form a nebula, gravity causes the nebula to collapse and spin, nuclear fusion occurs, and a protostar forms.
(B A protostar forms, nuclear fusion occurs, gases condense to form a nebula, and gravity causes the nebula to collapse and spin.
(C Gases condense to form a nebula, gravity causes the nebula to collapse and spin, a protostar forms, and nuclear fusion occurs.
(D A protostar forms, gases condense to form a nebula, gravity causes the nebula to collapse and spin, and nuclear fusion occurs.
The correct order of processes leading up to the formation of a main sequence star is : ( C ) Gases condense to form a nebula, gravity causes the nebula to collapse and spin, a protostar forms, and nuclear fusion occurs.
What is a main sequence star ?A main sequence star is a group of stars which forms a band of stellar types usually 90 percent when plotted on a graph ( spectrum vs luminosity) it also represents the life stages of a regular star in the galaxy.
In conclusion the correct order of the main sequence star is; Gases condense to form a nebula, gravity causes the nebula to collapse and spin, a protostar forms, and nuclear fusion occurs.
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A bicycle moves from rest to 8.0 m/s in 4.3 seconds. What was the acceleration?
Can please show me how you got it, I am so confused.
Answer:
1,86
Explanation:
V=V0+a x t
8 m/s=0 m/s + a x 4,3 s
8m/s=a x 4,3 s
a= 8m/s / 4,3 s
a=1,86
V=Last speed
V0=Initial speed
a=acceleration
t=time
calculate the power output of a machine that lifts a 50kg crate through a height of 20.0m in one minute
Answer:
power= work done/ time
power=mgh/time
mass(m) =50kg
acelleration due to gravity (g)= 10g/m^2
height(h) =20.0m
time = 1min
Explanation:
power =50×10×20 /1
power = 10,000watts
power =10 ×10^3kw
p =10 Kilowatt's
A 5.0 kg box is sitting on a scale in an elevator. Before the elevator moves, the scale reads 49.05 N. When the elevator accelerates into motion, the scale momentarily reads 46.75 N. If the acceleration due to gravity is 9.81 m/s2, what is the magnitude of the acceleration of the elevator? (1 point)
A) 0.46 m/s2
B) 0.57 m/s2
C) 0.87 m/s2
D) 0.91 m/s2
The magnitude of acceleration of the elevator is 0.46m/s². Details on how to calculate magnitude of acceleration can be found below.
How to calculate magnitude of acceleration?The magnitude of acceleration of the accelerator can be calculated by dividing the difference in force by the mass of the accelerator.
According to this question, a 5.0 kg box is sitting on a scale in an elevator. Before the elevator moves, the scale reads 49.05 N, however, when the elevator accelerates into motion, the scale momentarily reads 46.75 N.
Magnitude of acceleration = (49.05 - 46.75)/5
Magnitude of acceleration = 2.3/5
Magnitude of acceleration = 0.46m/s²
Therefore, the magnitude of acceleration of the elevator is 0.46m/s².
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A train travels a distance of 20miles for 50min. Calculate the speed of the train.
Answer:
24 mph
Explanation:
Speed = Distance / Time
Speed = 20 ÷ 5/6
Speed = 24 mph
NOTE: 5/6 is a fraction in this case and is equivalent to 50/60 and 60 minutes = 1 hour of course.
Hope this helped!
Answer:
[tex]\textsf {speed = 24 mph}[/tex]
Explanation:
[tex]\textsf {Formula used :}\\\implies \textsf {speed = distance/time}[/tex]
[tex]\mathsf {Given :}[/tex]
[tex]\implies \textsf {distance = 20 miles}[/tex]
[tex]\implies \textsf {time = 50 minutes = 5/6 hour}[/tex]
[tex]\textsf {Solving :}[/tex]
[tex]\implies \mathsf {speed = 20 \div 5/6 }[/tex]
[tex]\implies \mathsf {speed = 20 \times 6/5}[/tex]
[tex]\implies \mathsf {speed = 4 \times 6}[/tex]
[tex]\implies \textsf {speed = 24 mph}[/tex]
Which words best describe the archer's results?
OA. High precision, low accuracy
B. Low precision, low accuracy
OC. Low precision, high accuracy
D. High precision, high accuracy
The words best describe the archer's results are The correct option is A.
What is accuracy?When in an experiment, a value is measured 5 times, then if the values measured are same for most of the time or like three times out of five, it said to be accurate. The phenomenon is accuracy.
Precision is about comparing the values to each other then find them near to each other.
Given is an archer's targets on the target board.
Accuracy compares the experimental value to the theoretical value (desired target)
So, when all the values are close to each other but not nearest to the theoretical value, then it is said to be precise but not accurate.
Thus, the correct option is A.
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What is the equivalent resistance of the
following two resistors in parallel?
R₁
www
200 Ωپیشهl
250 Ω
Req =
Answer:
Approximately [tex]111\; {\rm \Omega}[/tex].
Explanation:
It is given that [tex]R_{1} = 200\; {\Omega}[/tex] and [tex]R_{2} = 250\; {\Omega}[/tex] are connected in a circuit in parallel.
Assume that this circuit is powered with a direct current power supply of voltage [tex]V[/tex].
Since [tex]R_{1}[/tex] and [tex]R_{2}[/tex] are connected in parallel, the voltage across the two resistors would both be [tex]V[/tex]. Thus, the current going through the two resistors would be [tex](V / R_{1})[/tex] and [tex](V / R_{2})[/tex], respectively.
Also because the two resistors are connected in parallel, the total current in this circuit would be the sum of the current in each resistor: [tex]I = (V / R_{1}) + (V / R_{2})[/tex].
In other words, if the voltage across this circuit is [tex]V[/tex], the total current in this circuit would be [tex]I = (V / R_{1}) + (V / R_{2})[/tex]. The (equivalent) resistance [tex]R[/tex] of this circuit would be:
[tex]\begin{aligned} R &= \frac{V}{I} \\ &= \frac{V}{(V / R_{1}) + (V / R_{2})} \\ &= \frac{1}{(1/R_{1}) + (1 / R_{2})}\end{aligned}[/tex].
Given that [tex]R_{1} = 200\; {\Omega}[/tex] and [tex]R_{2} = 250\; {\Omega}[/tex]:
[tex]\begin{aligned} R &= \frac{1}{(1/R_{1}) + (1 / R_{2})} \\ &= \frac{1}{(1/(200\: {\rm \Omega})) + (1/(250\; {\rm \Omega}))} \\ &\approx 111\; {\rm \Omega}\end{aligned}[/tex].