A heat pump has a coefficient of performance equal to 4.20 and requires a power of 1.75 kW to operate. (a) How much energy does the heat pump add to a home in one hour? (b) If the heat pump is reversed so that it acts as an air conditioner in the summer, what would be its coefficient of performance?

The weight of 15N should be hung at a distance of 4/3 units from the fulcrum, on the opposite side of the bar to a weight of 20N.

The fulcrum is attained equilibrium when the principle of moments is equal to zero. The principle of momentum is defined as the body is said to be balanced when the clockwise movement about the point is equal to the anticlockwise movement about the same point.

When a weight of 15N is hung on the bar, it produces an anticlockwise movement with the same magnitude, opposes the clockwise moment produced by the weight of 20N on the fulcrum.

To find the distance (d) at which the 15N weight should be hung, the distance from the 20N weight to the fulcrum is 1 unit.

20×1 = 15×d

d = 20/15

  =4/3 m

Thus, the weight of 15N should be hung by the distance of 4/3 units from the fulcrum, on the opposite side of the bar having the weight of 20N, to make the fulcrum to be at equilibrium.

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The tension force being supplied by the rope is 245 N.

The tension force on the given rope due to the weight of the lamp hanging from the rope is calculated by applying Newton's second law of motion as shown below;

T = mg

where;

T = 25 x 9.8

T = 245 N

Thus, the tension force being supplied by the rope is 245 N.

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The engineer must design an engine that can produce a force of over 3,100 Newtons.

A force is an energy that can cause change of motion. It can be a push or a pull. It also has both magnitude and direction, making it a vector quantity.

From the question;

total mass = mass of person + mass of cart

total mass = 80kg + 75kg

total mass = 155kg

acceleration = 20m/s²

The formula to be used;

F = m x a

F = 155kg x 20m/s²

F = 3,100N

In conclusion, the engineer needs a minimum force of 3,100 N in the engine to be able to power the cart.

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Answer:

a) y = 2.21 10⁻³ m, b)  y = 5.528 10⁻³ m

Explanation:

In the double-slit experiment the interferences occur at the positions

         d sin θ = m λ                    constructive interference

         d sin θ = (m + ½) λ           destructive interference

let's use trigonometry for the angle

          tan θ = y / L

as in this experiment the angles are very small

          tan θ = sin θ/cos θ = sin θ

          sin θ = y / L

we substitute

         d y / L = m λ                   constructive interference

         d y / L = (m + ½) λ          destructive interference

Let's answer the questions

a) first line of constructive interference me = 1

          y = m  λ L / d

          y = 1 647 10⁻⁹ 3.93 /1.15 10⁻³

          y = 2.21 10⁻³ m

b) second dark band m = 2

            y = (m + ½) λ L / d

            y = (2 + ½)  647 10⁻⁹ 3.93 /1.15 10⁻³

            y = 5.528 10⁻³ m

Answer

I feel the answer is C because it could cause mental and physical trauma

Explanation:

There is more to the Earth than what we can see on the surface. In fact, if you were able to hold the Earth in your hand and slice it in half, you'd see that it has multiple layers. But of course, the interior of our world continues to hold some mysteries for us. Even as we intrepidly explore other worlds and deploy satellites into orbit, the inner recesses of our planet remains off limit from us.

However, advances in seismology have allowed us to learn a great deal about the Earth and the many layers that make it up. Each layer has its own properties, composition, and characteristics that affects many of the key processes of our planet. They are, in order from the exterior to the interior – the crust, the mantle, the outer core, and the inner core. Let's take a look at them and see what they have going on.

Like all terrestrial planets, the Earth's interior is differentiated. This means that its internal structure consists of layers, arranged like the skin of an onion. Peel back one, and you find another, distinguished from the last by its chemical and geological properties, as well as vast differences in temperature and pressure.

Explanation:

A hypothetical charge that is situated at a single location in space is a point charge.a scale of length used to describe an electron's size, can be used to classify an electron size even though it is frequently referred to as a point charge.

The area of space immediately surrounding a charged particle (also known as a point charge or a source charge) develops an electric field. The electric field version of Coulomb's Law is represented by this. In fact, the remainder of the cosmos is the area of space surrounding a charged particle.

Point charges in physics refer to bodies that are exceedingly small in size relative to their distance from one another. Due to how simple it is to determine the attraction force or repulsion between them, we therefore treat them as point charges.

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Answer:

it is A

Explanation:

The current in the circuit is 2.5 A.

Voltage across the wire AX, V = 4 - 2 = 2V

Resistance per unit length of wire AX, R/l = 2 Ω/m

Length of the wire, l = 0.4 m

Resistance of the wire,

R = R/l x R

R = 2 x 0.4 = 0.8 Ω

According to Ohm's law, the current in the wire AX,

I = V/R

I = 2/0.8

I = 2.5 A

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Answer:

The fish gobbles the mosquito at height 18 cm.

Explanation:

Initial velocity, u = 3.7 m/s

horizontal distance, d = 28 cm

Angle, A = 39 degree

Let the time is t.

Horizontal distance = horizontal velocity x time

d =  u cos A x t

0.28 = 3.7 cos 39 x t

t = 0.097 s

Let the height is h.

Use the second equation of motion

\(h =u t-0.5 gt^2\\\\h= u sin A t - 0.5 gt^2\\\\h= 3.7 sin 39 \times 0.097 - 0.5\times 9.8\times 0.097\times0.097\\\\h =0.226 -0.046 \\\\h=0.18 m=18 cm\)

Answer:

In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration.

Explanation:

Graphs can help to demonstrate the qualitative relationship between a set of data by identifying patterns among these data.

Graphs can allow readers to identify a lot of information among a set of data. The most common information to be evaluated through the graphs is the existence of patterns between the data.

For example, a line graph can show the change in a variable over time, allowing readers to see if there is a consistent increase or decrease.

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Answer:

The tension in the rope if it is parallel to the slope is 24.31 N.

Explanation:

Given;

mass of the sled, m = 9 kg

angle of inclination of the slope, θ = 16⁰

The tension in the rope if it is parallel to the slope is calculated from the parallel component of the tension;

\(T_|_| = mgSin \theta\\\\T_|_| = 9 \times 9.8 \times sin(16^0)\\\\T_|_| = 24.31 \ N\)

Therefore, the tension in the rope if it is parallel to the slope is 24.31 N.

Answer:

I'm not sure but I think its aluminum

Let v denote the initial speed of the ball. The ball's position at time t is given by the vector

\(\mathbf r(t)=v\cos40^\circ\,t\,\mathbf i+\left(v\sin40^\circ\,t-\dfrac g2t^2\right)\,\mathbf j\)

where g is the acceleration due to gravity with magnitude 9.80 m/s^2.

The ball reaches the goal 13 m away at time t such that

\(10\,\mathrm m=v\cos40^\circ t\implies t=\dfrac{10\,\mathrm m}{v\cos40^\circ}\)

at which point it attains a height of 2.44 m, so that

\(2.44\,\mathrm m=v\sin40^\circ\left(\dfrac{10\,\mathrm m}{v\cos40^\circ}\right)-\dfrac g2\left(\dfrac{10\,\mathrm m}{v\cos40^\circ}\right)^2\)

\(2.44\,\mathrm m=(10\,\mathrm m)\tan40^\circ-\dfrac12\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)\left(\dfrac{100\,\mathrm m^2}{v^2\cos^240^\circ}\right)\)

\(\implies\boxed{v\approx3.75\dfrac{\rm m}{\rm s}}\)

Answer:

Conservation of Energy: Like all things, Stirling Engines follow the conservation of energy principle (all the energy input is accounted for in the output in one form or another). ... The hot one supplies all of the energy QH, while the cold one removes energy QC (a necessary part of the cycle).

Explanation:

Answer: Yes

Explanation: All the energy input is accounted for in the output in one form or another

Answer: If you meant 5 miles in 20 minutes than it’s 1 mile in 5 minutes

Explanation:

The car's average speed is

0.1875 • (the number of miles it covered)

Answer:

Yes

Explanation:

Answer:

B) In the near-ultraviolet

Explanation:

The best option to this problem is : In the near-ultraviolet

Answer:

1.4 * 10 ^-1 Ω

Explanation:

Hi,

For this question, we gotta use the formula

R = pL/A

p = The resistivity of your material at 20°C

L = length of the wire

A = cross-sectional area

The resistivity of tungsten is 5.60 * 10^-8 at 20°C

By plugging the values, we get:

R = (5.60 * 10^-8)(2.0)/(7.9*10^-7) = 1.4 * 10 ^-1 Ω

Answer:

natural convection

............

Answer:

An object in a motion when it is continuously changing its position based on a reference point and observed by a person or a device.

The capacitance of the capacitor is 1.7 * 10^-4 F. The capacitance will increase when the voltage is increased.

If we hold the capacitance constant, a higher voltage applied to the capacitor will result in a greater amount of electrical charge stored on the capacitor. Conversely, if we hold the voltage constant, a capacitor with a higher capacitance will be able to store more electrical charge. In other words, the capacitance and the voltage are directly proportional to the amount of electrical charge that can be stored on a capacitor.

We know that;

q = CV

C = q/V

C =  0.0024 C/12 V

C = 1.7 * 10^-4 F

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The velocity of this automobile as a function of time. At t = 5 seconds, the automobile is 90 meters from its initial position.

To determine the distance traveled by the automobile from its t = 0 initial position, we need to calculate the area under the velocity-time graph up to t = 5 seconds.

The graph shows the velocity of the automobile as a function of time. Let's assume that positive velocity represents forward motion, and negative velocity represents backward motion.

Since velocity represents the rate of change of displacement, the area under the velocity-time graph represents the displacement or distance traveled. In this case, the area will consist of two parts: the area above the x-axis (forward motion) and the area below the x-axis (backward motion).

To calculate the area, we can break it down into two separate integrals:

1. The area above the x-axis (forward motion):

Since the velocity is constant at 20 m/s for the first 4 seconds, the area is a rectangle:

Area1 = velocity * time = 20 m/s * 4 s = 80 m

2. The area below the x-axis (backward motion):

The velocity changes to -10 m/s at t = 4 seconds. From t = 4 seconds to t = 5 seconds, the velocity is -10 m/s. The area is a rectangle:

Area2 = velocity * time = -10 m/s * 1 s = -10 m

To find the total distance traveled, we add the absolute values of the areas:

Total distance = |Area1| + |Area2| = |80 m| + |-10 m| = 80 m + 10 m = 90 m

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Answer:

well i am sure you need this to so look really hard at this then delete it

Explanation:

1. The speed with which electrons move through a copper wire is typically 10-4 m s-1

.

a. Explain why is it that the electrons cannot travel faster in the conductor?

b. Explain why the electron drift produces heat?

1. a) collisons with the crystal lattice atoms b) collisions with lattice atoms transfers energy.

2. Explain in terms of atomic and electron movement, why resistance increases with temperature.

2. Electrons drift through the lattice, as temperature increases the lattice atoms vibrate more and this increases the probability of

collision and hence resistance to electrons has increased.

3. Calculate the resistance of an aluminum (ρ = 2.8x10-8 Ωm) wire that is 2.0 m long and of circular cross section

with a diameter of 1.5 mm.

3. 32 mΩ

4. Determine the length of tungsten (ρ = 5.6x10-8 Ωm) wire with a diameter of 1.0 mm that is used to make a 20.0 Ω resistor.

4. 280 m

5. A nichrome (ρ = 100x10-8 Ωm) wire has a diameter of 0.40 mm. Calculate the length of this wire needed to carry a current

of 30 mA when there is a potential difference of 12 V across it.

5. 50 m

6. A thin copper (ρ = 1.68x10-8 Ωm, but you don’t need it) wire 200 cm in length has a 9 V dry cell connected between its ends.

Determine the voltage drop that occurs along 30 cm of this wire.

6. 1.35 V

7. If the potential difference across the bulb in a camping lantern is 9.0 V, what is the potential difference across the battery used to

power it?

battery gives the voltage of 9.0 V to the lantern to use it.

8. How much current, in amperes, is in a lightning stroke that lasts 0.05 second and transfers 100 coulombs?

I = q/t = (100 C)/(0.05 s) =2000 A

9. Calculate the resistance of the filament in a light bulb that carries 0.4 A when 3.0 V is impressed across it.

V = IR R = V/I = 7.5 Ω

10. Electric socks, popular in cold weather, have a 90-ohm heating element that is powered by a 9-volt battery.

How much current warms your feet?

V = I/R = 0.1 A

11. Calculate the current of a lightning bolt that delivers a charge of 35 coulombs to the ground in a time of 1/1000 second.

11. I = q/t = 35 000 A.

12. Calculate the current where 10 coulombs of charge pass a point in 5 seconds.

12. I = V/R = 2 A

13. Two light bulbs designed for 120-V use are rated at 40W and 60W. Which light bulb has the greater filament resistance? Why?

13. More current flows in the 60-W bulb, which means the resistance of the filament is less.

P = IV = V2/R, R = V2/P = (120 V)2/(60 W) = 240 Ω; for the 40-W lamp, R = (120 V)2/(40 W) = 360 Ω

14. A battery does 18 joules of work on 3 coulombs of charge. What voltage does it supply?

14. V= E/q= (18 J)/(3 C) = 6V

15. A power line with a resistance of 2 ohms has a current of 80 A in it. The power dissipated in the line is

15. 12800 W.

2

16. A toaster oven is plugged into an outlet that provides a voltage difference of 120 V.

What power does the oven use if the current is 10A?

16. P = IV = 1200 W

17. A VCR that is not playing still uses 10.0 W of power. What is the current if the VCR is plugged into a 120 V electric outlet? 17.

17. P = IV I = P/V = 0.083 A

18. A flashlight bulb uses 2.4 W of power when the current in the bulb is 0.8 A. What is the voltage difference?

18. P = IV V = P/I = 3V

19. A refrigerator operates on average for 10.0 h a day. If the power rating of the refrigerator is 700 W, how much electrical energy

does the refrigerator use in 1 day? (make sure to convert to kW)

19. E = Pt = (0.7 kW)(10.0 h) = 7 kWhours

20. A TV with a power rating of 200 W uses 0.8 kWh in one day. For how many hours was the TV on during this day?

20. E = Pt t = E/P= 0.8 kWh/0.2 kW = 4 h

21. Calculate the voltage difference in a circuit with a resistance of 25 Ω if the current in the circuit is 0.5 A.

21. V = IR = 12.5 V

22. A current of 0.5 A flows in a 60 W light bulb when the voltage difference between the ends of the filament is 120 V.

What is the resistance of the filament?

22. R = V/I = 240 Ω

23. A toy car with a resistance of 20 Ω is connected to a 3 V battery. How much current flows in the car?

23. I = V/R = 0.15 A

24. The current flowing in an appliance connected to a 120 V source is 2 A. How many kilowatt-hours of electrical energy does the

appliance use in 4 h? (2 equations used & convert watts to kW)

24. E = Pt P = IV = 0.24 kW E = 0.96 kWh

25. A calculator uses 9 V battery & draws 0.1 A of current. How much power does it use?

25. P = IV = 0.9 W

26. A battery causes 250 mA to flow when it is applied to a light bulb with a resistance of 50 ohms. How much current would flow if

the same source were applied to a 12 ohm resistor?

26. voltage of the source: V = IR = 12.5 V I = V/R = 1.04 A

Given,

The length of each side of the square, l=90 ft

In the diagram, h represents the home plate, 1 is 1st base plate, 2 is 2nd base, 3 is the third base.

The displacement can be defined as the shortest distance between two points.

1st base

The distance from the home plate to 1st base is,

Thus the distance from home plate to 1st base is 90 ft

The shortest distance between the home plate and the 1st base is equal to the length of the side.

The displacement, in this case, is equal to the distance.

Thus the displacement of the player when he is at the 1st base plate is,

Thus the displacement of the player from home plate to 1st base is 90 ft

2nd base

The distance between the home plate and the second base is,

The distance covered by the player when he is at the second base is 180ft.

The displacement of the player from the home plate to 2nd base is given by the Pythagorean theorem.

That is,

Therefore, the displacement of the player as he reaches the second base is 127.28 ft.

3rd base

The distance covered by the player from the home plate to third base is,

Thus the distance covered by the player from home plate to the 3rd base is 270 ft.

The displacement, i.e., the shortest distance from the home plate to the third base is,

Thus the displacement of the player when he reaches the third base is 90 ft.

The home plate:

The distance covered by the player when he comes back to the home plate is,

Thus, the distance covered by the player when he scores the home run is 360 ft.

The displacement of the player when he reaches the home plate is zero. As the shortest distance from home plate to home plate is 0 ft.