Determine the focal length of a plano-concave lens (refractive index n =1.5) with 24 cm radius of curvature on its curve surface
1)-96 cm
2)-24 cm
3)-48 cm
4)-72 cm

Answer:

The energy transported per hour is 4.92 x 10⁻¹⁰ J.

Explanation:

Given;

root mean square strength of the field, [tex]E_{rms}[/tex] = 38.5 mV/m

area per hour, A = 1.25 cm²/hr = 1.25 x 10⁻⁴ m²/hr

The peak strength of the field is given by;

E₀ = [tex]E_{rms}[/tex]√2

E₀ = (38.5 mV)√2

E₀ = 54.45 mV

the average intensity is given by;

[tex]I_{avg} = \frac{c\epsilon E_o^2}{2}\\\\ I_{avg} = \frac{(3*10^8)(8.85*10^{-12})(54.45*10^{-3})^2}{2}\\\\I_{avg} = 3.936*10^{-6} \ W/m^2[/tex]

Energy transported per hour is given by;

[tex]E = \frac{P}{t} = \frac{I*A}{t} = (\frac{A}{t})(I)\\\\E = (1.25*10^{-4} \ \frac{m^2}{hr} )(3.936*10^{-6} \ \frac{W}{m^2} )\\\\E = 4.92*10^{-10} \ J[/tex]

Therefore, the energy transported per hour is 4.92 x 10⁻¹⁰ J.

Answer:

Explanation:

C

Answer:

Explanation:

Alcohol use C

Answer:

a) 23 m/s

Explanation:

       [tex]p_{o} = p_{f} (1)[/tex]

       [tex]p_{o} = m_{1} * v_{1o} + m_{2}* v_{2o} = 6.0 kg * 5.0 m/s + 2.0 kg * v_{2o} (2)[/tex]

        [tex]p_{f} = (m_{1} + m_{2} )* v_{f} = 8.0 kg* (-2.0 m/s) (3)[/tex]

       [tex]v_{2o} = \frac{-6.0kg* 5m/s -8.0 kg*2.0m/s}{2.0kg} = \frac{-46kg*m/s}{2.0kg} = -23.0 m/s (4)[/tex]

The speed of the 2.0-kg object before the collision will be 23 m/s.Option A is correct.

According to the law of conservation of momentum, the momentum of the body before the collision is always equal to the momentum of the body after the collision.

The given data in the problem is;

m₁ is the mass of objthe ct = 6.0-kg

v₁ is the speed moving = 5

m₂ is the mass of object 2 = 2.0 Kg

V is the final speed = 2.0 m/s

v₂ is the speed of the 2.0-kg object before the collision =?

According to the law of conservation of momentum;

Momentum before collision =Momentum after collision

[tex]\rm m_1v_1 + m_2v_2 = V(m_1 + m_2)\\\\(6 \times 5) + (2 \times v_2) = -2.0 \times (8) \\\\ \rm v_2 = \frac{-46}{2.0} \\\\ \rm v_2 =-23.0\ m/sec[/tex]

Hence the speed of the 2.0-kg object before the collision will be 23 m/s.Option A is correct.

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Answer:

Explanation:

The formula for kinetic energy to be used here is 1/2mv².

If the first particle is "particle a" and the second particle is "particle n"; there kinetic energies (K.E) will be

K.Eₐ = 1/2.m2v² = mv²

K.Eₙ = 1/2.2mv² = mv²

From the above, it can be said that there kinetic energies are the same.

NOTE that the m and v used in the question means mass and velocity respectively.

Answer:

Kelly's weight would be 688.47 Newtons.

Explanation:

1 Kilogram would be 9.81 Newtons.

It all depends on where Kelley is at the moment.

-- If she's on Mars, she weighs 229 N.

-- If she's on the Moon, she weighs 113N.

-- If she's on Earth, she weighs 686 N.

-- If she's in a space capsule coasting from one body to another, then there's no instrument that can measure any weight of her.

So it completely depends on where she happens to be at the moment.

Answer:

In this experiment the major sources of error were due many different factors, some of which included: restraints on the Voltage sensor, restraints on the actual apparatus, and faulty averages of the stopping potential.

Explanation:

The main sources of error in this experiment were caused by a variety of variables, including restrictions on the Voltage sensor, restrictions on the actual device, and inaccurate averages of the stopping potential.

When a substance absorbs electromagnetic radiation, a phenomenon known as the photoelectric effect causes electrically charged particles to be discharged from or within the material. When light strikes a metal plate, the action is frequently described as the ejection of electrons from the plate. In a more general definition, the substance may be solid, liquid, or gas, the radiant energy may take the form of infrared, visible, or ultraviolet light, X-rays, or gamma rays, and the discharged particles may include ions (electrically charged atoms or molecules) in addition to electrons.

Because of the perplexing concerns, it presented about the nature of light—particle versus wavelike behavior—that were finally answered by Albert Einstein in 1905, the phenomenon was critically important in the development of modern physics.

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The blue line with triangles are a cold front. The red line with half circles are a warm front. The black H is high pressure. The black L is low pressure. The black dot is overcast skies. Finally the white circle with a line down and 4 lines off of that line is 40-knot wind

idk and dont understand

Answer:

Wind speed.

Explanation:

I took the test and I promise this is right.

Answer:

Explanation:

The mass of the rock can be found by using the formula

[tex]m = \frac{f}{a} \\ [/tex]

f is the force

a is the acceleration

From the question we have

[tex]m = \frac{400}{20} = \frac{40}{2} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

Reversing the polarity of the battery reverses the polarity in the circuit.

Explanation:

In a DC circuit, the polarity of the potential difference and the current is determined by the polarity of the battery or the power source.

Reversing the polarity of the battery reverses the polarity in the circuit.

In the case of current, the direction of the movement of the electrons is reversed and in the case of the potential difference, this is measured with respect to a minimum fly in general taken as zero.

Explanation:

Unbalanced Forces in Action

Unbalanced forces can change the motion of an object in two ways. ... Second, when unbalanced forces act on a moving object, the velocity of the object will change. Remember that a change in velocity means a change in speed, direction or both speed and direction.

Answer:

pf = 3750000 kg.m/s

F = 175000 N

Explanation:

Constant Acceleration

An object moves with constant acceleration if its velocity changes uniformly in time.

If we call vo to the initial speed, vf the final speed, and t the time, then the acceleration is calculated as:

[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]

The new stealth helicopter was traveling at vo=180m/s and changed to vf=250 m/s in t=6 seconds, thus the acceleration was:

[tex]\displaystyle a=\frac{250-180}{6}[/tex]

[tex]a=11.67~m/s^2[/tex]

Please note this number is shown rounded to the nearest hundredth, but it was stored in the calculator's memory with full precision. This fact affects the next calculation as will be noted below.

The acceleration must be produced for some net force that can be calculated by:

F = m.a

Where m=15000 Kg is the mass of the helicopter. Thus:

F = 15000 * 11.67

F = 175000 N

The above product would lead to the inaccurate result of 175050 if the acceleration would have not used with its full representation in the calculator's memory.

The momentum of an object of mass m and velocity v is:

p = m. v

The final momentum of the helicopter is:

pf = m.vf = 15000*250 m/s

pf = 3750000 kg.m/s

Note: When performing calculations over intermediate results, it's important to keep them as accurate as possible to preserve the accuracy of the final result.

Answer:

Polar

Explanation:

Took the test

This question is incomplete, the complete question is;

A loop of radius r = 3.0 cm is placed parallel to the xy-plane in a uniform magnetic field B = 0.75 Tˆk.

The resistance of the loop is 18 Ω. Starting at t = 0, the magnitude of the field decreases uniformly to zero in 0.15 seconds.

What is the magnitude of the electric current produced in the loop during that time?

Answer

a 2.1 mA

b 0.79 mA

c 1.7 mA

d 0.20 mA

e 3.9 mA

Answer: option (b) 0.79 mA is the correct answer

Explanation:

Given that;

radius r = 3 cm = 0.03 m

Magnetic field B = 0.75

Resistance R = 18

time t = 0.15s

Area A = πr² = π(0.03)² = 0.002827 m²

we know that

Induced EMF ∈ = -BA / T

and ∈ is also = IR

so, IR = -BA/t

I = -BA / Rt

we substitute our values into the equation

I = [- (-0.75 × 0.002827)] / [18 × 0.15]

= 0.002120 / 2.7

= 0.0007851 A ≈ 0.00079 A ≈ 0.79 mA ( milliamperes )

Therefore option (b) 0.79 mA is the correct answer

Answer:

See the explanation below.

Explanation:

Of course yes, after my explanation you will understand very well how to analyze this type of problems.

First, we must differentiate the weight of the mass, the mass has units of kilograms or pounds, while the weight is the product of the mass by gravitational acceleration. In this way, we have the following formula for the weight of anybody.

w = m*g

where:

w = weight [N] (units of Newtons]

m = mass [kg]

g = gravity acceleration = 9.81 [m/s²]

When we have the product of these units [kg]*[m/s²], We are always going to get as a result the units of Newtons [N], The Newton is a unit of force.

Now, to solve this problem we must use Newton's second law, which tells us that the sum of forces on a body must be equal to the product of mass by acceleration.

ΣF = m*a

where:

ΣF  = forces acting over the gymnast [N]

m = mass = 55 [kg]

a = desacceleration = 6*9.81 = 58.86 [m/²]

Now we have two forces acting over the gymnast the first one is his or her weight (the mass by the gravity acceleration) and the second force is the one made it by his or her legs upwards in order to be standing. Let's take as positive signs the movements and forces upwards and negative downwards

- (m*g) + Fl = m*a

where:

Fl = force made it by the legs [N]

As the deceleration is upward because it prevents the person from continuing to go down, it is taken as a positive sign.

- (55*9.81) + Fl = (55*58.86)

Fl =  (55*58.86) + (55*9.81)

Fl = 3776.85 [N]

I hope you can understand :)

Answer:

The five elements of successful teamwork

-Communication: Effective communication is the most important part of teamwork and involves consistently updating each person and never assuming that everyone has the same information. ...

-Delegation: Teams that work well together understand the strengths and weaknesses of each team member. ...

-Efficiency: ...

-Ideas: ...

-Support:

Answer:

The student must change the launch angle from 20º to 45º to maximize the horizontal distance.

Explanation:

The dart experiments a parabolical motion, which is the combination of horizontal uniform motion and vertical uniform accelerated motion due to gravity, in which effects from air friction and Earth's rotation can be neglected. The equations of motion are described below:

[tex]x = x_{o}+v_{o}\cdot t \cdot \cos \theta[/tex] (1)

[tex]y = y_{o}+v_{o}\cdot t\cdot \sin \theta +\frac{1}{2}\cdot g\cdot t^{2}[/tex] (2)

Where:

[tex]x_{o}[/tex], [tex]y_{o}[/tex] - Initial coordinates of the dart, measured in meters.

[tex]x[/tex], [tex]y[/tex] - Current coordinates of the dart, measured in meters.

[tex]v_{o}[/tex] - Initial velocity of the dart, measured in meters per second.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]t[/tex] - Time, measured in seconds.

[tex]\theta[/tex] - Launch angle, measured in sexagesimal degrees.

According to the statement, we need to determine the launch angle when [tex]\Delta x = x-x_{o} > 0[/tex], [tex]\Delta y = y-y_{o}= 0[/tex] and [tex]v_{o} > 0[/tex]. Then, we obtain the following system of linear equations:

[tex]\Delta x = v_{o}\cdot t \cdot \cos \theta[/tex] (1b)

[tex]v_{o}\cdot \sin \theta + \frac{1}{2}\cdot g \cdot t = 0[/tex] (2b)

By (2b), we clear time as follows:

[tex]t = -\frac{2\cdot v_{o}\cdot \sin \theta}{g}[/tex]

And it is applied in (1b) afterwards:

[tex]\Delta x = -\frac{2\cdot v_{o}^{2}\cdot \sin\theta \cdot \cos\theta}{g}[/tex]

[tex]\Delta x = -\frac{v_{o}^{2}\cdot \sin 2\theta}{g}[/tex] (3)

Where [tex]\Delta x[/tex] is the horizontal distance, measured in meters.

In order to determine the launch angle such that distance is maximized, we require the first and second derivatives of the function. That is:

First derivative

[tex]\Delta x' = -\frac{2\cdot v_{o}^{2}\cdot \cos 2\theta}{g}[/tex] (4)

Second derivative

[tex]\Delta x'' = \frac{2\cdot v_{o}^{2}\cdot \sin 2\theta}{g}[/tex] (5)

By equalizing (4) to zero, we find the following trigonometric equivalence:

[tex]\cos 2\theta = 0[/tex]

[tex]2\cdot \theta = 90^{\circ}[/tex]

[tex]\theta = 45^{\circ}[/tex]

A launch angle of 45º is a critical point of (3). If we know that [tex]g< 0[/tex] and [tex]\theta = 45^{\circ}[/tex] in (5), then [tex]\Delta x'' < 0[/tex], which means that critical point determined above leads to a maximum distance. Then, the student must change the launch angle from 20º to 45º to maximize the horizontal distance.

Answer:

45.51 J

Explanation:

Energy in relation to vertical displacement = P.E.

P.E. (potential energy) = mgh

m = 134.6g = 0.1346 kg

g = 9.81m/s²

h = 34.8m

since, P.E = mgh = 0.1346 × 9.81 × 34.8

= 45.51J

Answer:

a) the centripetal force causing the cat to turn in a circular path is due to friction between the car's tyres and the surface of the road.

b)

1) a larger centripetal force is required if the car travels faster

2) a larger centripetal force is needed when the bend is less curved.

3) when a car has more passengers, the mass of the car increases, therefore, a larger force is required to move the car.

Explanation:

The friction between the car's tire and the surface provides centripetal force and if the car travels faster, the bend is curved, or the car has more passengers it requires a larger centripetal force.

When an object is moving in a curve path then a force is acting radically in the object this force is called centripetal force, this force helps to maintain the object in the curve e.g. if a car is moving in a well, so the centripetal force is responsible, so the car is not falling. The SI unit used to represent centripetal force is Newton.

A. The friction between the car's tire and the curve surface is responsible for providing the centripetal force, and it also depends on the car's speed.

B.  If a car is traveling faster than a larger centripetal force is required to maintain the curve path of the car, means if the friction between the tire and surface decreases the centripetal force also decreases.

When the bend is less curved, the radius of the curve increase and thus require more centripetal force.

When people in the car increase then the mass of the car also increases so due to this the gravitation force is now more on the car so more centripetal force I required to maintain the curve path of the car.

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Answer:

Q = 48341.7 Joules.

Explanation:

Given the following data;

Mass, m = 257g

Initial temperature, T1 = 18°C

Final temperature, T2 = 63°C

Specific heat capacity of water, c = 4.18 J/g°C.

*To find the quantity of heat absorbed*

Heat capacity is given by the formula;

[tex] Q = mcdt[/tex]

Where;

dt = T2 - T1

dt = 63 - 18

dt = 45°C

Substituting the values into the equation, we have;

[tex] Q = 257*4.18*45[/tex]

Q = 48341.7 Joules.

Therefore, the amount of heat absorbed is 48341.7 Joules.

Answer:

a) W = 2746.8[J]

b) W = 2992.05 [J]

Explanation:

Work is defined as the product of force by distance. We must bear in mind that the force that performs the work is the one that acts in the same direction of displacement.

For this case, we must calculate the weight of the woman, the weight is defined as the product of mass by gravity.

[tex]w=m*g\\[/tex]

where:

w = weight [N] (units of Newtons]

m = mass = 56 [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]w=56*9.81\\w=549.36[N][/tex]

a)

[tex]W=F*d[/tex]

where:

F = weight = 549.36[N]

d = distance = 5 [m]

[tex]W = 549.36*5\\W = 2746.8[J][/tex]

b)

The new mass will be the combination of the mass of the woman plus that of the load.

[tex]m_{new} = 56+5\\m_{new}=61[kg][/tex]

[tex]w_{new}=61*9.81\\w_{new}=598.41[N][/tex]

The new work done.

[tex]W =598.41*5\\W=2992.05[J][/tex]

Work does the human heart do if it uses 180 N of force to pump blood 0.3 meters to the lungs 39 joule.

Work in physics is the energy that is transferred to or from an item when a force is applied along a displacement. In its simplest form, it equals the product of the force's magnitude and the distance travelled for a constant force directed in the direction of motion.

Work = force x distance. In units, Joules = Newtons x meters.

W = F.d

F = 180 N d=0.3 m

W = F.d

W = (180)(0.3)

W = 39 j

Work does the human heart do if it uses 180 N of force to pump blood 0.3 meters to the lungs 39 joule.

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Answer:

but you didn't give the equation the question is incomplete

Answer:

Initial velocity

Explanation:

Answer:

 v = 29.4 m / s

Explanation:

For this exercise we can use the conservation of mechanical energy

Lowest starting point.

          Em₀ = K = ½ m v²

final point. Higher

          [tex]Em_{f}[/tex] = U = m g h

Let's use trigonometry to lock her up

          cos 60 = y / L

          y = L cos 60

Height is the initial length minus the length at the maximum angle

           h = L - L cos 60

           h = L (1- cos 60)

energy is conserved

         Em₀ = Em_{f}

          ½ m v² = mgL (1 - cos 60)

         v = 2g L (1- cos 60)

let's calculate

          v² = 2 9.8 3.0 (1- cos 60)

          v = 29.4 m / s

Answer:

lane departure warnings

Explanation:

Answer:

W=31.99 N

Explanation:

W= 8 N (N= kg*m/ s^2)

W= m* g

8 N= m * 9.8 m/s^2

m= 0.816 kg

m*4= (0.816)4

= 3.264 kg

W= mg

= (3.264 kg)(9.8 m/s^2)

W=31.99 N

Answer:

Explanation:

Generally, the energy required to move an electron from one energy level to another energy level is referred to as quantum energy. An atom will absorb energy when it's electron(s) move from a lower energy level (ground state) to a higher energy level (excited state) and will emit energy when it's electron(s) move from a higher energy level to a lower energy level.

Since, electrons do not stay in the excited state forever, they indeed prefer the ground state and thus will always return to the ground state. When an electron thus return to the ground state, it sheds off the excess energy that took it to the excited state thus it can be said that more energy is required to take an electron to it's excited state.

Answer:

Explanation:

When an atom absorbs energy it will go up x number levels. When it admits energy it will go down to its previous energy level and emit the same exact amount of energy that was absorbed.

Answer:

 θ = 1.21  10⁻² rad

Explanation:

The double slit experiment is described for constructive interference

           d sin θ = m λ

where d is the separation between the slits, λ the wavelength used, m a stereo that represents the order of interference

The first order of interference corresponds to m = 1 and the separation of the slits is d = 5.2 10⁻⁵ m

        sin θ = m λ / d

        θ = sin⁻¹ (m λ / d)

let's calculate

          θ = sin⁻¹ (1 631 10⁻⁹ / 5.2 10⁻⁵)

          θ = 1.21  10⁻² rad

Explanation:

the world of introductory physics, Newton's second law is one of the most important laws you'll learn. It's used in almost every chapter of every physics textbook, so it's important to master this law as soon as possible.

We know objects can only accelerate if there are forces on the object. Newton's second law tells us exactly how much an object will accelerate for a given net force.

\Large a=\dfrac{\Sigma F}{m}a=

m

ΣF