A section of a sphere has a radius of curvature of 0.72 m. If this section is painted with a reflective coating on both sides, what is the focal length of:

Answers

Answer 1

Answer:

The value is  [tex]f = 0.36 \ m[/tex]

Explanation:

From the question we are told that

  The radius of curvature is  [tex]R = 0.72 \ m[/tex]

   

Generally the radius of curvature is mathematically represented as

        [tex]R = 2f[/tex]

Here [tex]f[/tex] is the focal length hence

       [tex]f = \frac{R}{2}[/tex]

=>     [tex]f = \frac{0.72}{2}[/tex]

=>     [tex]f = 0.36 \ m[/tex]


Related Questions

Im need some help with this please

Answers

The answer is D, human.


Happy Friday!!!

Answer:

c) Aeroplane

Explanation:

The aeroplane has the greatest mass than the other three objects, so it experiences the greatest gravitational force. Hence, the option (c) is the answer.

Why does a stop sign appear red?

Answers

Answer:

because it’s suppose to be red like a stop light.

Explanation:

So it tells you to stop

A wire is carrying current vertically downward. What is the direction of the force due to Earth's magnetic field on the wire?
A wire is carrying current vertically downward.
What is the direction of the force due to Earth's magnetic field on the wire?
a) horizontally towards the east
b) horizontally towards the west
c) horizontally towards the south
d) horizontally towards the north vertically upward

Answers

Answer: The correct option is A ( horizontally towards the east)

Explanation:

Magnetic field is a region around a magnet or a current- carrying conductor, where a magnetic force is experienced. The magnetic effect of electric current was first discovered in the early 1820 by Oersted. Using a wire that had current flowing through it and a pivoted magnetic needle, he discovered that the direction of deflection depended on the direction of the current and whether the wire was above or below the needle.

From the way the needle turns when current when current carrying wire is held parallel to it, he therefore concluded that:

--> a current has magnetic field all round it,

--> the magnetic field is in a direction perpendicular to the current.

The above discovery was now modified in Fleming's left hand rule which states that when conductor carrying current is placed in a magnetic field, the conductor will experience a force perpendicular to both the field and the flow of current.

Therefore from the question, a vertical wire carrying current in DOWNWARD direction is placed in a HORIZONTAL magnetic field directed to the NORTH. The direction of the force on the wire is to the EAST.

If 65 kW is to be transmitted over two 0.100 ohm lines, estimate how much power is saved if the voltage is stepped up from 120 V to 1200 V

Answers

Answer: 5.91kw

Explanation:

given data:

power = 65kw

voltage stepped up = 120v t0 1200

R 0.100

Solution:

when the it is stepped to 120v

[tex]P = VI \\65000/ 120I\\ I = 541.7A\\[/tex]

power loss

[tex](I^{2} )R*2\\= (541.7^{2})0.100*2\\= 58536.2w[/tex]

when it is stepped to 1200v

[tex]\frac{65000}{1200} \\ I = 54.17A\[/tex]

[tex](I^{2} )R*2\\= (54.17^{2})0.100*2\\= 586.9w[/tex]

total power saved

[tex]= 65kw - 58.5kw - 0.59kw\\= 5.91kw[/tex]

motion is a change in

Answers

i think it’s position measured by distance and time.

Two forces of 50 N and 30N respectively, are acting on an object. Find the net force (in N) on the object if

Answers

A) the forces are acting in the same direction.. B) Together, forces are acting in opposite directions

Answer:

A) 80 N

B) 20 N

Explanation:

A) If the forces acting are in the same direction, then the net force will be a sum of both so many faces..

Thus;

ΣF = 50 + 30

ΣF = 80 N

B) If the forces are acting in the in opposite directions with the larger force pointing in the positive y-axis then, the net force is;

ΣF = 50 - 30

ΣF = 20 N

2
Look at the circult dlagram.
Direction
of current
Battery
Bulb-
What type of circuit is shown?
A. open series circult
B. closed series circuit
C. open parallel circult
D. closed parallel circult

Answers

C : I did this already

The direction of the current from the positive to the negative battery terminals and the fact that the bulbs are connected in parallel to each other suggests that this circuit is a Closed Parallel Circuit. The correct option is D.

What is the difference between open and closed circuits?

An open circuit and a closed circuit are two types of electrical circuits that describe the flow of electrical current through a circuit.

An open circuit is a circuit in which there is a break in the path of the current, meaning that the current cannot flow through the circuit. In an open circuit, the switch is in the "off" position or there is a broken wire, and so no electrical current can flow through the circuit. This means that there is no voltage or electrical energy being transferred from the source to the load.

On the other hand, a closed circuit is a circuit in which there is a complete path for the current to flow through, meaning that the current can flow through the circuit. In a closed circuit, the switch is in the "on" position, and there is a continuous path for the current to flow from the source to the load and back to the source. This means that there is voltage and electrical energy being transferred from the source to the load.

Here in this question,

The direction of the current from the positive to the negative battery and the fact that the bulbs are connected in parallel to each other suggests that this circuit is a Closed Parallel Circuit.

In a closed parallel circuit, the components are connected in parallel to each other, meaning that they are connected to the same two points in the circuit and the current has multiple paths to flow through. The voltage across each component is the same, and the total current flowing through the circuit is divided among the components according to their resistance.

In contrast, an open series circuit is a circuit in which the components are connected in series, meaning that they are connected end to end in a single path, with no other branch points for the current to follow. If one component fails, the circuit becomes open and the current stops flowing.

Therefore, based on the information provided, the circuit described in the question is a Closed Parallel Circuit.

To learn about Ohm's law click:

brainly.com/question/29775285

#SPJ7

A student adds two vectors of magnitudes 48 m and 22 m. What are the maximum and minimum possible values for the resultant of these two vectors.

Answers

Answer:

Maximum=70 m

Minimum=26 m

Explanation:

Vector Addition

Since vectors have magnitude and direction, adding them takes into consideration not only the magnitudes but also their respective directions. Two vectors can be totally collaborative, i.e., point to the same direction, or be totally opposite. In the first case, the magnitude of the sum is at maximum. Otherwise, it's at a minimum.

Thus, the maximum magnitude of the sum is 48+22 = 70 m and the minimum magnitude of the sum is 48-22= 26 m

A person holds a ladder horizontally at its center. Treating the ladder as a uniform rod of length 4.15 m and mass 7.98 kg, find the torque the person must exert on the ladder to give it an angular acceleration of 0.396 rad/s2.

Answers

Answer:

4.535 N.m

Explanation:

To solve this question, we're going to use the formula for moment of inertia

I = mL²/12

Where

I = moment of inertia

m = mass of the ladder, 7.98 kg

L = length of the ladder, 4.15 m

On solving we have

I = 7.98 * (4.15)² / 12

I = (7.98 * 17.2225) / 12

I = 137.44 / 12

I = 11.45 kg·m²

That is the moment of inertia about the center.

Using this moment of inertia, we multiply it by the angular acceleration to get the needed torque. So that

τ = 11.453 kg·m² * 0.395 rad/s²

τ = 4.535 N·m

The Torque will be "4.535 N.m".

Given:

Mass of ladder,

m = 7.98 kg  

Length of ladder,

L = 4.15 m

The moment of inertia will be:

→ [tex]I = \frac{mL^2}{12}[/tex]

     [tex]= \frac{7.98\times (4.15)^2}{12}[/tex]

     [tex]= \frac{7.98\times 17.2225}{12}[/tex]

     [tex]= 11.45 \ kg.m^2[/tex]

hence,

The torque will be:

→ [tex]\tau = 11.453\times 0.395[/tex]

      [tex]= 4.535 \ N/m[/tex]

Thus the above approach is correct.      

Learn more about torque here:

https://brainly.com/question/19247046

The angle between an incident
ray and the mirror is 40°.
1) What is the angle of reflection?​

Answers

Answer:

1) 50°

Explanation:

We need to find the angle of incidence first before finding the angle of reflection.

Angle of incidence = 90° - 40°

                                = 50°

Since the angle of incidence is the same as the angle of reflection, the angle of reflection here would be 50°.

what is the object's position at 6s?​

Answers

Answer:

6sec and 8 postion

Explanation:

you pick up a 3.8 kg can of paint from the ground a lift it to a height of 1.4 m. you hold the can stationary for half a minute, waiting for a friend on a ladder to take it. how much work do you do duting this time (when the can of paint is stationary)?

Answers

Answer:

No work

Explanation:

During the time of holding the can stationary, no work is being done by the person carrying the can.

The can is simply at rest.

Work is done when a force is applied to move a body through a certain distance.

  Work done  = force x distance

In the instance given in this problem, only when the paint was lifted up is work done.

When the paint is  stationary and being supported by the person, no work is done.

The terms transverse or longitudinal are often used to describe the types of pulses. To what feature of a pulse do these terms refer:____________

Answers

Explanation:

Transverse pulse or waves are those in which elements of the pulse move perpendicular to the propagation of the pulse. Whereas, Longitudinal waves are those in which elements of the wave are in same direction as the propagation of the wave. For example Light is a transverse pulse whereas sound is a longitudinal wave.  

Question 12 of 20
To produce a magnetic field, what does an electromagnet require?
A. A solenoid with no current flowing through it
B. A current flowing through a coil of wire
C. A core made from a magnetic material
D. A copper core

Answers

Answer:

B a current flowing through a coil of wire :)

Explanation:

In an oil drop experiment, a drop with a weight of 1.9 x 10-14 N was suspended when the potential difference between 2 plates that were 63 mm apart was 780 V. What was the charge on the drop?

Answers

Answer:

Study More You will get it :L

The greater the change in the speed of light in different media
the greater the angle of

Answers

Answer:

the angle at which light bends when it enters a different medium depends on its change in speed. The greater the change in speed, the greater the angle of refraction is. For example, light refracts more when it passes from Air to Diamond then it does when it passes from Air to wate.

Answer: Refraction

Explanation:

Thomas the Tank Engine (a train) is going 80 m/s and slows down to 30 m/s over a period of 30s. What is his deceleration? Acceleration= (final velocity-initial velocity)/ time A. -1.67 m/s/s B. 0.67 m/s/s C. -50 m/s/s D. 50 m/s/s

Answers

Answer: D

Explanation:

Plz help

Fill in the blank with the correct observation from the simulation.
As the days go on, the distance that the moon is from the sun in the night sky

A. Stays the same
B. Decreases
C. Increases

Answers

Starting at New Moon, The visual distance increases for about 2 weeks, then decreases for about the next 2weeks, until the next New Moon.

On the average, it changes by about 12° per day.

A diffraction pattern is formed on a screen 150 cm away from a 0.500-mm-wide slit. Monochromatic 546.1-nm light is used. Calculate the fractional intensity I/Imax at a point on the screen 4.10 mm from the center of the principal maximum.

Answers

Solution :

The expression for the intensity of light is given by :

[tex]$I=I_{max}\left(\frac{\sin \frac{\pi a \sin \theta}{\lambda}}{\frac{\pi a \sin \theta}{\lambda} }\right)^2$[/tex]

For a small angle, θ

sin θ = tan θ

        [tex]$=\frac{y}{L}$[/tex]

Therefore the above equation becomes,

[tex]$I=I_{max}\left(\frac{\sin \frac{\pi a y}{\lambda L}}{\frac{\pi a y}{\lambda L} }\right)^2 $[/tex]

The given data is

λ = 546.1 nm

L = distance between the slit and the screen = 140 cm

  = 1.40 m

a = width of the slit

  = [tex]$0.50 \times 10^{-3} \ m$[/tex]

Therefore,

[tex]$I=I_{max}\left(\frac{\sin \frac{\pi \times 0.50 \times 10^{-3} \times 4.10 \times 10^{-3}}{546.1 \times 10^{-9} \times 1.20}}{\frac{\pi \times 0.50 \times 10^{-3} \times 4.10 \times 10^{-3}}{546.1 \times 10^{-9} \times 1.20} }\right)^2 $[/tex]

  [tex]$=\left(\frac{0.170}{9.82}\right)^2$[/tex]

 [tex]$= 2.89 \times 10^{-4} \ I_{max}$[/tex]

Therefore the fractional intensity is   [tex]$\frac{I}{I_{max}}= 2.89 \times 10^{-4} $[/tex]

a 1220 kg automobile travels at 75 m/s. what net work would be required to bring it to a stop ​

Answers

Answer:

W = - 3431250 [N]

Explanation:

In order to solve this problem, we must use the theorem of work and energy conservation. This theorem tells us that the initial mechanical energy of a body plus the work done on this body must be equal to the final mechanical energy of the body. We must remember that the mechanical energy of a body is equal to the sum of kinetic energies plus potential energy plus elastic energy.

In this problem, we only have kinetic energy.

[tex]E_{1}+W_{1-2}=E_{2}\\where:\\E_{1}=E_{pot}+E_{kine}+E_{elas}\\E_{pot} = 0\\E_{elas}=0\\E_{kine}=\frac{1}{2} *m*v^{2}[/tex]

And we have:

m = mass = 1220 [kg]

v = velocity = 75 [m/s]

As the carriage stops the final kinetic energy is zero.

Now replacing:

[tex]\frac{1}{2} *1220*(75)^{2} +W_{1-2}=0\\W_{1-2}= - 3431250[N][/tex]

Note: The negative force means that the force has to be carried out by the carriage. That is, no external force acts on the car to stop it.

Forces that cancel each other are called_ forces \

Answers

Answer:

balanced forces

A whale comes to the surface to breathe and then dives at an angle 24 degrees to the horizontal surface of the water. The whale continues in a straight line 145 m. What are the horizontal and vertical components of the displacement of the whale?

Answers

Given that,

A whale dives at an angle of 24 degrees to the horizontal surface of the water.

The whale continues in a straight line 145 m.

To find,

The horizontal and vertical components of the displacement of the whale.

Solution,

The horizontal component of displacement is :

[tex]d_x=d\cos\theta\\\\=145\times \cos(24)\\\\=132.46\ m[/tex]

The vertical component of displacement is :

[tex]d_y=d\sin\theta\\\\=145\times \sin(24)\\\\=58.97\ m[/tex]

Hence, the horizontal and vertical components of the displacement of the whale are 132.46 m and 58.97 m.

Which has more momentum, a 2000 lb car moving at 100 km/hr or a 4000 lb truck moving at 50 km/hr ?

Answers

Answer:

The truck and car have the same momentum.

Explanation:

[tex]m_1[/tex] = Mass of car = [tex]2000\ \text{lb}=2000\times0.45359237\ \text{kg}[/tex]

[tex]v_1[/tex] = Velocity of car = [tex]\dfrac{100}{3.6}\ \text{m/s}[/tex]

[tex]m_2[/tex] = Mass of truck = [tex]4000\times0.45359237\ \text{kg}[/tex]

[tex]v_2[/tex] = Velocity of truck = [tex]\dfrac{50}{3.6}\ \text{m/s}[/tex]

Momentum of car

[tex]p_1=m_1v_1\\\Rightarrow p_1=2000\times0.45359237\times \dfrac{100}{3.6}\\\Rightarrow p_1=25199.58\ \text{kg m/s}[/tex]

Momentum of the truck

[tex]p_2=m_2v_2\\\Rightarrow p_2=4000\times0.45359237\times \dfrac{50}{3.6}\\\Rightarrow p_2=25199.58\ \text{kg m/s}[/tex]

Both the truck and car have the same momentum of [tex]25199.58\ \text{kg m/s}[/tex].

What is the final velocity of an object that starts from rest and accelerates uniformly at 4
m/s2 over a distance of 8 m?

Answers

Answer:

8m/s

Explanation:

Given parameters:

Initial velocity  = 0m/s

Acceleration  = 4m/s²

Distance  = 8m

Unknown:

Final velocity  = ?

Solution:

To solve this problem, we use the right motion equation and find the unknown.

The right motion equation to solve this problem is given as :

        v²  = u²  + 2aS

v is the final velocity

u is the initial velocity

 a is the unknown acceleration

S is the distance

     Now insert the parameters and solve;

             v²  = 0² + 2 (4) (8)

             v² = 64

             v = 8m/s

A diver 50 m deep in 10∘C fresh water exhales a 1.0-cm-diameter bubble. What is the bubble's diameter just as it reaches the surface of the lake, where the water temperature is 20∘C?

Answers

Answer:

18.2mm

Explanation:

D = 50m

T1 = 10+273 = 283K

T2 = 20+273 = 293K

R1 = 5x10^-3

Absolute pressure at 50m

P1 = pA + pwateer x g x d

= 101000+ 1000x9.81x50

= 591500pa

New volume of bubble

= P1v1/T1 = p2v2/T2

= 125x10^-9 x 591500x293/101000*283

= 757.9x10^-9m³

R2 = 9.2x10^-3

D2 = 18.2mm

Or 1.82cm

The water drops fall at regular intervals from a tap 5 m above the ground. The third drop is leaving the tap at the instant the first touches the ground. How far above the ground is the second drop at that instant?
I will mark brainliest​

Answers

Answer:

The second drop is 3.75 m above the ground

Explanation:

Free Fall Motion

A free-falling object falls under the sole influence of gravity without air resistance.

If an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is [tex]g = 9.8 m/s^2[/tex].

The distance traveled by a dropped object is:

[tex]\displaystyle y=\frac{gt^2}{2}[/tex]

If we know the height h from which the object was dropped, we can find the time it takes fo hit the ground:

[tex]\displaystyle t=\sqrt{\frac{2y}{g}}[/tex]

When the first drop touches the ground there are two more drops in the air: the second drop still traveling, and the third drop just released from the tap.

The total time taken for the first drop to reach the ground is:

[tex]\displaystyle t_1=\sqrt{\frac{2*5}{g}}[/tex]

[tex]t_1 = 1.01\ s[/tex]

Half of this time has taken the second drop to fall:

[tex]t_2 = 1.01\ s/2=0.505\ s[/tex]

It has fallen a distance of:

[tex]\displaystyle y_2=\frac{9.8(0.505)^2}{2}[/tex]

[tex]y_2 = 1.25\ m[/tex]

Thus its height is:

h = 5 - 1.25 = 3.75

The second drop is 3.75 m above the ground

A 125 g pendulum bob hung on a string of length 35 cm has the same period as when the bob is hung from a spring and caused to oscillate. What is the spring’s elastic constant?a) 3.5 N/mb) 5.2 N/mc) 1.9 N/md) 27 N/m

Answers

Answer:

k = 3.5 N/m

Explanation:

It is given that the time period the bob in pendulum is the same as its time period in spring mass system:

[tex]Time\ Period\ of\ Pendulum = Time\ Period\ of\ Spring-Mass\ System\\2\pi \sqrt{\frac{l}{g}} = 2\pi \sqrt{\frac{m}{k}[/tex]

[tex]\frac{l}{g} = \frac{m}{k}\\\\ k = g\frac{m}{l}[/tex]

where,

k = spring constant = ?

g = acceleration due to gravity = 9.81 m/s²

m = mass of bob = 125 g = 0.125 kg

l = length of pendulum = 35 cm = 0.35 m

Therefore,

[tex]k = (9.81\ m/s^2)(\frac{0.125\ kg}{0.35\ m})\\\\[/tex]

k = 3.5 N/m

A 3 kg mass is travelling in a circle of 0.1 m radius with a speed of 2 m/s. What is the centripetal acceleration?

Answers

a = v² / R = (2 m/s)² / (0.1 m) = 40 m/s²

Shelley is in an elevator that is traveling downward and slowing down at a rate of
0.950 m/s2. If Shelley has a mass of 73.2 kg, what is her apparent weight during this
period?

Answers

Answer:

N = 648.55[N]

Explanation:

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

∑F = m*a

where:

∑F =  Forces applied [N]

m = mass = 73.2 [kg]

a = acceleration = 0.950 [m/s²]

Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.

By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

[tex]-m*g + N = -m*a\\[/tex]

where:

g = gravity acceleration = 9.81 [m/s²]

N = normal force (or weight) measured by the scale = 83.4 [N]

Now replacing:

[tex]-(73.2*9.81)+N=-73.2*0.950\\-718.092+N=-69.54\\N = -69.54+718.092\\N = 648.55[N][/tex]

The acceleration has a negative sign, this means that the elevator is descending at that very moment.

Two friends grab different sides of a textbook and pull with forces of 6.7 N to the east and 4.4 N to the west, respectively. What would be the magnitude and direction of the force a third friend would need to exert on the textbook in order to balance the other two forces?

Answers

Explanation:

This equation for acceleration can be used to calculate the acceleration of an object that is acted on by a net force. For example, Xander and his scooter have a total mass of 50 kilograms. Assume that the net force acting on Xander and the scooter is 25 Newtons. What is his acceleration? Substitute the relevant values into the equation for acceleration:

Answer:

a=Fm=25 N50 kg=0.5 Nkg

The Newton is the SI unit for force. It is defined as the force needed to cause a 1-kilogram mass to accelerate at 1 m/s2. Therefore, force can also be expressed in the unit kg • m/s2. This way of expressing force can be substituted for Newtons in Xander’s acceleration so the answer is expressed in the SI unit for acceleration, which is m/s2:

a=0.5 Nkg=0.5 kg⋅m/s2kg=0.5 m/s2

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