The focal length of the contact lens needed for this prescription is -25 cm.
To calculate the focal length of the contact lens needed for this prescription, we can use the formula:
1/f = 1/v - 1/u
where f is the focal length, v is the distance of the object from the lens, and u is the distance of the image from the lens.
In this case, the near point is 60 cm, so the distance of the image from the lens (u) is -60 cm (negative because the image is virtual). The object is placed 25 cm in front of the eye, so the distance of the object from the lens (v) is -25 cm.
Plugging these values into the formula, we get:
1/f = 1/-25 - 1/-60
Simplifying:
1/f = -0.04
Multiplying both sides by -1:
-1/f = 0.04
Dividing both sides by 0.04:
f = -25
So the focal length of the contact lens needed for this prescription is -25 cm.
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A 88.5 kgkg skater moving initially at 2.40 m/sm/s on rough horizontal ice comes to rest uniformly in 3.52 ss due to friction from the ice.
The friction force that is being exerted by the ice to the skater ould be 46.7 N.
To determine the friction force exerted in the skater, we use Newton's Second law of motion which relates force, acceleration and the mass. It is expressed as follows:
F = m (a)
where m = mass of the body = 68.5 kg
The acceleration, a, of the moving body is calculated by dividing the initial velocity with the total time. Thus,
a = 2.40 m/s / 3.52 s = 0.682 m/s^2
Substituting the values to the equation of force, we will have
F = m (a) = 68.5 kg (0.682 m/s^2) = 46.7 N
Thus, the friction force that is being exerted by the ice to the skater ould be 46.7 N.
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How could lewis and the other staff members of pearson physicians group prepare for natural disasters, such as the tornado?.
Lewis and other staff members of Pearson Physicians Group can prepare for natural disasters, such as the tornado: by being proactive, building storm shelters and by being on the lookout for impending disaster warnings.
How to prepare for natural disaster?By being proactive during natural disasters involves ensuring that safety facilities are put into consideration during the construction of building, following established disaster response guidelines, and also providing for basic essential supplies for staff and patients.
To prepare for natural disaster: assess your risk – internally and externally, create an emergency management plan, create a crisis communications plan and assemble emergency supplies.
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Please answer this question sqdancefan
Answer:
(D) 4
Explanation:
The percentage error in each of the contributors to the calculation is 1%. The maximum error in the calculation is approximately the sum of the errors of each contributor, multiplied by the number of times it is a factor in the calculation.
density = mass/volume
density = mass/(π(radius^2)(length))
So, mass and length are each a factor once, and radius is a factor twice. Then the total percentage error is approximately 1% +1% +2×1% = 4%.
_____
If you look at the maximum and minimum density, you find they are ...
{0.0611718, 0.0662668} g/(mm²·cm)
The ratio of the maximum value to the mean of these values is about 1.03998. So, the maximum is 3.998% higher than the "nominal" density.
The error is about 4%.
_____
Additional comment
If you work through the details of the math, you will see that the above-described sum of error percentages is just an approximation. If you need a more exact error estimate, it is best to work with the ranges of the numbers involved, and/or their distributions.
Using numbers with uniformly distributed errors will give different results than with normally distributed errors. When such distributions are involved, you need to carefully define what you mean by a maximum error. (By definition, normal distributions extend to infinity in both directions.) While the central limit theorem tends to apply, the actual shape of the error distribution may not be precisely normal.
Answer:
D. 4Explanation:
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justoko2
which of the following substances is a base? ammonia, distilled water, lemon juice, or vinegar
a 0.29 kg harmonic oscillator has a total mechanical energy of 3.6 j. if the oscillation amplitude is 0.22 meters, what is the oscillation frequency f?
If the oscillation amplitude is 0.22m, from a 0.29kg harmonic oscillator which has a total of mechanical energy 3.6j, the oscillation frequency is 4.141Hz.
What is oscillation frequency?It is a number of oscillations in the one-time unit, says per second. For example, a pendulum that takes 0.5s to make one full oscillation has a frequency of 1 oscillation per 0.5s or 2 oscillations / second.
How to calculate the oscillation frequency?
mass (m) = 0.29kg
Total energy (E) = 3.6j
amplitude (x) = 0.22m
E = 1/2 k*x^2
k = 2*E / x^2
= 2 * 3.6 / 0.22^2
= 148.76 N/m
Frequency (v) = 1/2π √k/m
= 1/2*3.14 * √148.76 / 0.22
= 4.141Hz
Therefore, the oscillation frequency is 4.141Hz.
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Three two-port circuits, namely Circuit 1 , Circuit 2 , and Circuit 3 , are interconnected in cascade. The input port of Circuit 1 is driven by a 6 A de current source in parallel with an internal resistance of 30Ω. The output port of Circuit 3 drives an adjustable load impedance ZL. The corresponding parameters for Circuit 1, Circuit 2, and Circuit 3, are as follows. Circuit 1: G=[0.167S0.5−0.51.25Ω] Circuit 2: Circuit 3: Y=[200×10−6−800×10−640×10−640×10−6]S Z=[33534000−3100310000]Ω a) Find the a-parameters of the cascaded network. b) Find ZL such that maximum power is transferred from the cascaded network to ZL. c) Evaluate the maximum power that the cascaded two-port network can deliver to ZI.
a) The A-parameters of the cascaded network are defined by (4 points)Answer:a_11 = 0.149 S^0.5 - 0.0565a_12 = -0.115 S^0.5 - 0.0352a_21 = 136 S^0.5 - 133a_22 = -89.5 S^0.5 + 135b) Find ZL such that maximum power is transferred from the cascaded network to ZL. (2 pointsZ). The maximum power transfer to load impedance ZL occurs when the load is equal to the complex conjugate of the source impedance.
We can calculate the source impedance as follows: Rs = 30 Ω || 1/0.167^2 = 31.2 ΩThe equivalent impedance of circuits 2 and 3 connected in cascade is: Zeq = Z2 + Z3 + Z2 Z3 Y2Z2 + Y3 (Z2 + Z3) + Y2 Y3If we substitute the corresponding values: Zeq = 6.875 - j10.75ΩNow we can determine the value of the load impedance: ZL = Rs* Zeq/(Rs + Zeq)ZL = 17.6 - j8.9Ωc) Evaluate the maximum power that the cascaded two-port network can deliver to ZI. (2 points). The maximum power that can be delivered to the load is half the power available in the source.
We can determine the available power as follows: P = (I_s)^2 * Rs /2P = 558 mW. Now we can calculate the maximum power transferred to the load using the value of ZL:$$P_{load} = \frac{V_{load}^2}{4 Re(Z_L)}$$$$V_{load} = a_{21} I_s Z_2 Z_3$$So,$$P_{load} = \frac{(a_{21} I_s Z_2 Z_3)^2}{4 Re(Z_L)}$$Substitute the corresponding values:$$P_{load} = 203.2 m W $$. Therefore, the maximum power that can be delivered to the load is 203.2 mW.
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a plane is flying horizontally with speed 198 m/s at a height of 3210 m above the ground, when the package is dropped from a plane. The acceleration of gravity is 9.8 m/s^2.
a second package is thrown downward from the plane with a vertical speed v1=78m/s. what is the magnitude of the total velocity of the package at the moment it is thrown as seen by an observer on the ground? answer in units of m/s.
The magnitude of the total velocity of the package at the moment it is thrown as seen by an observer on the ground is D = 193m/s 15.2s = 2934 m.
What is velocity ?
velocity is the prime indicator of the position as well as the rapidity of the object
Sol-
1. 0.5gt^2 = 2010 m.
4.9t^2 = 2010.
t = 20.3 s. = Fall time.
D = Xot. = 193m/s 20.3s = 3909 m.
2. V=sqrt(Xo^2+Yo^2)=sqrt(193^2+58^2) = 202 m/s.
3. Vot + 0.5gt^2 = 2010 m.
58t + 4.9t^2 = 2010.
4.9t^2 + 58t - 2010 = 0.
Use the quadratic formula we are get
t = 15.2 s. = Fall time
D = 193m/s 15.2s = 2934 m.
D = 193m/s 15.2s = 2934 m.
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If friction is ignored and the ball is dropped, it experiences a gain in and a decrease in a
Answer: A gain in kinetic energy and a decrease in Potential energy
Explanation:
An object was thrown at a certain angle above the ground.It reaches a maximum height of 42.50 meters and hits back the ground 76 meters
1.find the time of flight
2.what is the initial velocity
3.find the angle of the projectile
Answer:
Explanation: Please see my attached calculations.
Which of the following best explains what creates this convection current?
options:
The rotation of Earth makes the air above it rotate, but not the same over land and water.
Because of its mass, Earth's gravity creates a high pressure area over both the land and water.
Salt in the ocean makes it more dense than the land, so its gravity pulls more on the air above it.
During the evening, the land cools off more quickly than the water. The cooler land cools the air above it, while the warmer water warms the air above it. These differences in air temperature create the convection.
Answer:
During the evening, the land cools off more quickly than the water. The cooler land cools the air above it, while the warmer water warms the air above it. These differences in air temperature create the convection.
Explanation:
sorry I took forever
What is the initial (starting) volume of water in the graduated cylinder? ______mL
The initial (starting) volume of water in the graduated cylinder can easily be determined by observing the level of water on the cylinder through the water's meniscus.
The initial volume of water in the cylinder during a laboratory experiment is determined by observing the level of water on the cylinder.
A measuring cylinder can be graduated by 1 mL and can measure up 100 mL, 150 mL, 200 mL or more.
To determine the accurate measurement of initial volume of water in the graduated cylinder, this measurement should be taken as follows;
Read off the position of the water meniscus at eye levelAvoid shaking the water before taking the measurementThus, the initial (starting) volume of water in the graduated cylinder can easily be determined by observing the level of water on the cylinder through the water's meniscus.
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The big five personality trait affects people negatively if they have to much of it? Which trait is it?
The term personality traits has to do with the essentials of a person. One of the five big personality trait that affects people negatively if they have to much of it is neuroticism.
Personality traitsThe term personality traits refers to those traits that characterize an individual. They have the capacity to affect a person positively or negatively.
One of the five big personality trait that affects people negatively if they have to much of it is neuroticism.
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The starting velocity was 0 m/s, and the final velocity was -7.68 m/s. Based on this, what was the average velocity of the rock
Formula: v = s+f/2
v = average velocity
s = starting velocity
f = final velocity
Use what we are given and solve.
v = 0+(-7.68)/2
v = -7.68/2
v = -3.84
Best of Luck!
rutherford created a planetary model for atoms after his experiments. imagine if rutherford's idea that electrons radiate energy while orbiting around a nucleus was true. which other model or scientific idea would have been strengthened by this?
Rutherford's idea that electrons radiate energy while orbiting around a nucleus would have strengthened the idea of quantum mechanics, which explains the behavior of particles at the subatomic level.
what is mechanics ?
Mechanics is a branch of science that studies the behavior of physical objects, their interactions, and the forces that act on them. It is sometimes referred to as the fundamental science, as it provides the underlying principles of many other sciences, such as engineering, aeronautical science, and medicine.
Mechanics is divided into two main branches: classical mechanics and quantum mechanics. Classical mechanics studies the motion of macroscopic objects, such as automobiles and aircraft, and is a cornerstone of engineering and the physical sciences. Quantum mechanics is the study of the behavior of microscopic objects, such as atoms and molecules, and is a cornerstone of modern chemistry and physics.
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b) What is work? Write down the types of work.
*2–20. determine the angle θ for connecting member a to the plate so that the resultant of f a fa and f b fb is directed along the positive x axis. also, what is the magnitude of the resultant force?
The angle θ for connecting member a to the plate so that the resultant of f a fa and f b fb is directed along the positive x axis are:
Fa=8sin54.93 in x direction
Fb=6sin40 in x direction
Resultant=10.4
What is magnitude?The term magnitude is defined as the “how much of a quantity”. For instance, magnitude can be used for explaining the comparison between the speeds of a car and a bicycle. It can also be used to explain distance travelled by an object or to explain the amount of an object in terms of its magnitude.
In Physics, magnitude is defined as maximum extent of the size and the direction of an object. Magnitude is used as a common factor in the vector and scalar quantities. By definition, we know that the scalar quantities are those quantities that have magnitude only. Whereas the vector quantities are those quantities that have both magnitude and direction.
There are the different ways in which magnitude can be used. Some of them are:
Magnitude of the earthquakeMagnitude of the charge on an electronMagnitude of the forceMagnitude of the displacementMagnitude of the gravitational force.The magnitude of a number, unlike magnitude of a physical quantity, is not relative to a scale or set of units: the magnitude of 100 is 100. By contrast, magnitude of a ruler is 12 in inches but is 30.48 in centimeters. Outside of the pure mathematics one has to be careful to specify the units in which the magnitude of some quantity is measured.
Therefore magnitude of resultant is:
=\(\sqrt{8sin54+936sin40}\)
=10.4
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Help asapppppppppppppppppp
2. How much current is in a circuit that includes a 1.5-volt battery and a
bulb with a resistance of 2 ohms?
Answer:
V = IR
I = V/R
= 1.5 / 2
= 0.75 A
Define g and give its value on the surface of the earth
G is commonly associated in the physics world to be Gravity. On earth it is 9.80665, though it is often rounded to 9.8.
what tests how one variable is affected by another
A. Observation B. Forecast C. Prediction D.Experiment?
the traits of friends
Answer:
someone you trust the most
Explanation:
Which element forms more com-
pounds than all the other elements
combined?
Answer:
Terms in this set (7) Which element forms more compounds than all the other elements combined? Carbon.
Explanation:
Hope its helps you ✌️
How much force is required to keep a 2-kg object moving to the right with a constant speed of 6.0 m/s?
A. 0 m/s
B. .33 m/s
C. 3 m/s
D. 12 m/s
The force required to keep a 2 kg object moving to the right with a constant speed of 6.0 m/s is calculated to be 0 N.
It is given that the mass of the object m is 2 kg.
As the body is said to be moving with constant speed, its acceleration would be rate of change of velocity, which would be zero.
Acceleration a = 0
Now, let us calculate the force required to move the 2 kg object. From Newton's second law, we know the expression, F = m a.
where,
m is mass
a is acceleration
F = m a = 2 × 0 = 0 N
Thus, the required force to move the object in right direction is calculated to be 0 N.
The given options have inappropriate units. They should be in Newtons.
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An image is formed by a mirror but not by the same cemented wall. why?
Can someone solve all of thesee
The force applied in the first case is 9200 N. In the second case, the force applied is less than the maximum force, so the groceries remain in the bag. The acceleration in the last case is 15 m/s².
What is force?A force is an influence in physics that can change the motion of an object. A force can cause a mass object to change its velocity, or accelerate. Intuitively, force can be described as a push or a pull. A force is a vector quantity because it has both magnitude and direction. The term "force" has a specific meaning in science. At this level, it is perfectly acceptable to refer to a force as a push or a pull. A force is not something that an object possesses or possesses. Another object applies a force to another. The concept of a force is not restricted to living or non-living things.
Here,
1. F=ma
m=4600 kg
a=2 m/s²
F=4600*2
=9200 N
2. Fₙ=250 N
m=20 kg
a=5m/s²
F=20*5
=100 N
F<Fₙ
Yes, The groceries will stay in bag.
4. Fₙ=30000 N
n=20
mₙ=75*20
=1500 kg
mₓ=500 kg
m=1500+500
=2000 kg
F=ma
30000=2000*a
a=15 m/s²
For first case, the force exerted is 9200 N. For second case, the force exerted is less than maximum force so the groceries will stay in bag. For last case, the acceleration is 15 m/s².
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55. What is the instantaneous speed of the point of the disk that makes contact with the surface?
A) zero m/s
B) 5.0 m/s
C) 7.1 m/s
D) 7.5 m/s
E) 10.0 m/s
The instantaneous speed of the point of the disk that makes contact with the surface is zero m/s (Option A).
To determine the instantaneous speed of the point of the disk that makes contact with the surface, we must consider the following terms:
Instantaneous speed: The speed of an object at a specific point in time.Point of contact: The point where the disk touches the surface.The answer to the question is A) zero m/s. The reason for this is that the point of contact between the disk and the surface is stationary for an instant, as it constantly changes due to the rotation of the disk. At that specific moment, the instantaneous speed of the point of contact is zero.
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Look at the diagram below that shows information about the sun, Earth, and moon. Use that information to calculate and compare the gravitational forces between the Earth and the Sun, and the Earth and the Moon.
i. The gravitational force between the earth and sun can be obtained as follow:
Mass of earth (M₁) = 5.987×10²⁴ KgMass of sun (M₂) = 1.989×10³⁰ KgDistance apart (r) = 1.5×10¹¹ mGravitational constant (G) = 6.67×10¯¹¹ Nm²/Kg²Gravitational force (F) =?F = GM₁M₂ / r²
F = (6.67×10¯¹¹ × 5.987×10²⁴ × 1.989×10³⁰) / (1.5×10¹¹)²
F = 3.53×10²² N
Thus, the gravitational force between the earth and sun is 3.53×10²² N
ii. The gravitational force between the earth and moon can be obtained as follow:
Mass of earth (M₁) = 5.987×10²⁴ KgMass of moon (M₂) = 7.347×10²² KgDistance apart (r) = 3.844×10⁸ mGravitational constant (G) = 6.67×10¯¹¹ Nm²/Kg²Gravitational force (F) =?F = GM₁M₂ / r²
F = (6.67×10¯¹¹ × 5.987×10²⁴ × 7.347×10²²) / (3.844×10⁸)²
F = 1.99×10²⁰ N
Thus, the gravitational force between the earth and moon is 1.99×10²⁰ N
How do i compare the gravitational forces?Gravitational force between the earth and sun (G₁) = 3.53×10²² NGravitational force between the earth and moon (G₂) = 1.99×10²⁰ NComparison =?Comparison = G₁ / G₂
G₁ / G₂ = 3.53×10²² / 1.99×10²⁰
G₁ / G₂ = 177
Cross multiply
G₁ = G₂ × 177
Thus, we can say that the gravitational force between the earth and sun is 177 times bigger than the gravitational force between the earth and moon
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Question 5 of 10
What are two things that happen when a home computer scanner uses
electromagnetic waves?
A. Red light shines on patterns of black and white, recording the
pattern of reflected light.
B. Objects are exposed to X-rays, which either pass through or are
absorbed by the objects.
C. A silicon chip releases electrons by the photoelectric effect,
producing an image.
D. A charge-coupled device captures visible light that is reflected off
an object
Answer: B. Objects are exposed to X-rays, which either pass through or are
absorbed by the objects.
C. A silicon chip releases electrons by the photoelectric effect,
producing an image.
Explanation:
10)
The population of humans living on the Earth has increased tremendously due to scientific discoveries and technology. Which
statement BEST summarizes how science and technology have contributed to human population growth?
A)
Science and technology have increased the human birth rate.
B)
Science and technology have been crucial in opening up new areas for
human development.
Science and technology have allowed for an increased emphasis on
education and the arts.
C)
D)
Science and technology have increased food and reduced death rates due
to illness and malnutrition.
The correct answer would be
D. Science and technology have increased food and reduced death rates due to illness and malnutrition.
I took this on USATestPrep, it's 100% right
Objects with masses of 141 kg and 494 kg are separated by 0.396 m. A 74.8 kg mass is placed midway between them.
1 ) Find the magnitude of the net gravitational force exerted by the two larger masses on the 74.8 kg mass.
The value of the universal gravitational constant is 6.672 × 10−11 N · m^2 /kg^2.
Answer in units of N.
2 ) Leaving the distance between the 141 kg and the 494 kg masses fixed, at what distance from the 494 kg mass (other than infinitely remote ones) does the 74.8 kg mass experience a net force of zero?
Answer in units of m.
( 1) The net gravitational force between the 74.8 kg mass is 8.09 x 10⁻⁵ N.
( 2) The distance from the from the 494 kg mass where the middle mass experiences net zero force is 0.258 m.
What is net gravitational force on the middle mass?
The net gravitational force acting on the middle mass is calculated by applying Newton's law of universal gravitation as shown below.
F = ( GmM ) / ( R² )
where;
G is universal gravitation constantm is the mass of the middle massM is the mass of the first massR is the distance of separation between the two massesThe force between the first mass and the middle mass is calculated as;
F' = ( 6.672 x 10⁻¹¹ x 141 x 74.8 ) / ( 0.198² )
F' = 1.8 x 10⁻⁵ N
The force between the third mass and the middle mass is calculated as;
F'' = ( 6.672 x 10⁻¹¹ x 494 x 74.8 ) / ( 0.198² )
F'' = 6.29 x 10⁻⁵ N
The net gravitational force on the middle mass;
F (net) = 6.29 x 10⁻⁵ N + 1.8 x 10⁻⁵ N
F ( net ) = 8.09 x 10⁻⁵ N
Let the distance of zero net force from the 141 kg mass = d.
then the distance from the 494 kg mass = 0.396 m - d
F' = ( 6.672 x 10⁻¹¹ x 141 x 74.8 ) / ( d² )
F' = 0.704 x 10⁻⁶ / d²
F'' = ( 6.672 x 10⁻¹¹ x 494 x 74.8 ) / ( 0.396 - d )²
F'' = 2.47 x 10⁻⁶ / ( 0.396 - d )²
for zero net force, the two forces must be equal
0.704 x 10⁻⁶ / d² = 2.47 x 10⁻⁶ / ( 0.396 - d )²
0.704 (0.396 - d )² = 2.47d²
(0.396 - d )² = ( 2.47d² ) / ( 0.704 )
(0.396 - d )² = 3.51d²
0.396 - d = √ ( 3.51d² )
0.396 - d = 1.87d
1.87d + d = 0.396
d (1.87 + 1) = 0.396
d (2.87) = 0.396
d = 0.396 / 2.87
d = 0.138 m
The distance from the 494 kg mass = 0.396 - 0.138 m = 0.258 m
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