Which terms describe the purpose of antennas on devices that use radio waves?

transmit and receive
modify and amplify
amplify and receive
modify and transmit

Answer:

I think ur wrong to say force doesn't change an object velocity

Explanation:

Force affects how objects move. They change the direction of motion of an object that is already moving. Since force causes a change in the speed or direction of an object, we may say that force causes changes in an object velocity.

Answer:4.2 miles/hour

Explanation:

220 each side = 880 meters total

880/3.5 = 251 is how many meters per minute

multiply by 60 to get per hour

Friction is not always negligible, as it can have significant effects on the behavior of objects in motion.

Friction is a force that opposes the motion of two surfaces in contact with each other. The magnitude of the frictional force depends on the nature of the surfaces in contact, the force pressing the surfaces together, and the relative motion between the surfaces.

In some cases, the effects of friction can be ignored because they are small compared to other forces at play. For example, in situations where an object is moving through a fluid, such as air or water, the effects of friction may be negligible compared to the forces of drag and buoyancy.

In other situations, the effects of friction cannot be ignored. For example, in a car's braking system, the friction between the brake pads and the rotor is necessary to slow down and stop the car. Without this friction, the car would not be able to come to a complete stop.

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any two uses of good conductor of heat are

aluminium, cooper, metal are good conductor of heat and they are used for making utensils.

gold, silver, are also good conductor of heat they are used for making jewelleries.

The voltage measured by the oscilloscope is 2 volts.

An oscilloscope is a device used to display and analyze the waveform of electronic signals. The voltage scale on an oscilloscope is usually calibrated in volts per division. This means that each division on the screen represents a certain amount of voltage.

In the given scenario, the oscilloscope is set in the 0.5 volts per division scale. This means that each division on the screen represents 0.5 volts of voltage. The signal measures four whole divisions, which means the total voltage can be calculated by multiplying the number of divisions by the volts per division.

Therefore, the value of voltage can be calculated as follows:

4 divisions x 0.5 volts per division = 2 volts

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Answer:

The compound formed has ionic bonds and is a crystalline solid

Explanation:

A metal plus a nonmetal chemical combine to form an ionic compound, with ionic bonds

Answer:

The value is \(t = 5.124 \ s\)

Explanation:

From the question we are told that

   The height of the tree is \(s = 20 \ m\)

    The angle the ball leaves is  \(\theta = 45^o\)

    The initial velocity  is  \(u = 30.0 \ m/s\)

Generally the vertical of the ball's initial velocity is mathematically evaluated as

      \(u_y = u * sin (45)\)

=>   \(u_y =- 30 * sin (45)\)

=>   \(u_y = -21.21 \ m/s\)

Here  \(u_y\) is negative because it is in the direction of the negative y-axis

Generally from kinematic equation we have

      \(s = u_yt + \frac{1}{2} g t^2\)

=>   \(20= -21.21 t +4.9 t^2\)

=>   \(4.9 t^2 -21.21 t- 20= 0\)

Solving using quadratic formula we have that

        \(t = 5.124 \ s\)

Explanation:

Bear in mind that the 13A fuse in the plug is not related to the 2A that your appliance draws. By the time the appliance causes the fuse to blow it is too late to protect the appliance.

The fuse rating is based upon the cable size between the plug and the point of failure. If the flex is sized to handle the full 3kW load, then a 13a fuse is reasonable. But if it is a lamp with skinny flex that is only intended to carry the 2A of the load, then protecting it with a 13A fuse risks further damage and possible ignition of the cord, and consequential building damage.

If you are aware of the core size of the cable, and have access to a set of copper tables, and know what the upper design limit is on the insulation temperature, then it is reasonable to make a judgement like you suggest.

If not, the easy decision is to rate the plughead fuse to suit the rating plate on the device. You know that the cable is sized to suit at least that load, so it is a sensible way to chose the fuse.

(1) The initial velocity of the ball is 7.8 m/s.

(2a) The time of motion of the baseball is 6.5 seconds.

(2b) The horizontal distance traveled by the baseball is 206.8 m.

(3) The height of fall of the bullet  before hitting the target is 0.078 m.

The given parameters include;

h = Vyt + ¹/₂gt²

where;

h = 0 +  ¹/₂gt²

t = √(2h/g)

t = √(2 x 8)/9.8

t = 1.28 s

x = Vxt

Vx = x/t

Vx = 10/1.28

Vx = 7.8 m/s

The given parameters include;

\(T = \frac{2u \times sin(\theta)}{g} \\\\T = \frac{2 (45) \times sin(45)}{9.8} \\\\T = 6.5 \ s\)

x = Vxt

x = (ucosθ)t

x = (45 cos(45)) x (6.5)

x = 206.8 m

The given parameters include;

x = Vxt

t = x/Vx

t = 100/800

t = 0.125 s

h = ¹/₂gt²

h =  ¹/₂(9.8)(0.125)²

h = 0.078 m

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The total energy of the spring is 3.92 J.

Step 1: Given:

the mass of the cat is m = 4 kg.

The amplitude of the SHM is A = 0.05

The elastic potential energy of the spring having a spring force constant k is given by,

\(U_{s} = \frac{1}{2} kx^{2}\)

As we know that the kinetic energy of a body of mass m and having a speed v is given by,

\(E_{K} = \frac{1}{2} mv^{2}\)

​The gravitational potential energy is given by,

\(U_{G} = mgy\)

​Where m is the mass of the body, g is the acceleration due to gravity, and y is the vertical height of the body.

Finally the sum of these three energy is:

\(E_{total} = U_{s} + E_{K} + U_{G}\)

Step 2: (a) When the cat is at its highest point, then at the highest point of the motion the spring has its natural unstretched length i.e. x=0, so from equation (1), the elastic potential energy of the spring will be:

\(U_{s} = 0\)

At the highest point, the speed is also zero, so  the kinetic energy will be,

\(E_{K} = 0\)

At the highest point, y = 2A, so the gravitational potential energy will be,

\(U_{G} = mg(2A)\\= 4 Kg * 9.8 ms^{-2} * 2 * 0.05 m\\= 3.92 J\)

Hence, total energy is given as:

\(E_{total} = 0 + 0+ 3.92 = 3.92 J\)

Elastic potential energy is the energy that is saved when a force is used to deform an elastic object. The object holds onto the energy until the force is released, at which point it springs back into shape while performing work. The object may be compressed, stretched, or twisted during the deformation.

Elastic energy is a type of potential energy because when anything is temporarily stressed, it stores energy in the links between its atoms. The object may have been stretched or compressed, causing this stress.

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a) The ratio of the electric charge on each conductor to the potential difference (i.e., voltage) between them is used to express capacitance.

b) The area of the plates, the spacing between them, and the type of insulating material or dielectric between them are the three variables that have an impact on a parallel-plate capacitor's capacitance.

c) The area of each plate, the dielectric material separating the plates, and the distance between the plates all affect the capacitance of a parallel plate capacitor.

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Answer:

2) 6.22 × 10^-13

3) 4.56 × 10^-4

Explanation:

Frequency is a fundamental concept in physics and refers to the number of occurrences of a repeating event per unit of time. The frequency of the 2nd excited normal mode of the standing sound wave in the pipe is 255 Hz.

In simpler terms, frequency describes the pitch or "highness" or "lowness" of a sound. A higher frequency corresponds to a higher pitch, while a lower frequency corresponds to a lower pitch. For example, a high-pitched sound like a whistle has a higher frequency than a low-pitched sound like a bass drum.

The frequency of the 2nd excited normal mode of a standing sound wave in the pipe can be determined using the formula:

\(f = (2n - 1) * (v/4L)\)

In this case, the speed of sound in air is given as 340 m/s and the length of the pipe is 1 m.

Plugging the values into the formula:

\(f = (2 * 2 - 1) * (340 / (4 * 1))\\= 3 * (340 / 4)\\= 255 Hz\)

Therefore, the frequency of the 2nd excited normal mode of the standing sound wave in the pipe is 255 Hz.

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The force of friction between the ball and the grass is 309.98 N.

What is Friction?

It occurs as a result of the microscopic irregularities on the surfaces that interlock and resist relative motion. The amount of friction between two surfaces depends on factors such as the nature of the surfaces in contact, the force pressing the surfaces together, and the relative speed between the surfaces. Friction can be beneficial in some situations, such as in walking or driving a car, but it can also be a hindrance in others, such as in machines where it causes wear and tear on moving parts.

To calculate the force of friction, we can use the formula:

Friction force = coefficient of friction × normal force

The normal force is the force that the ground exerts on the ball and is equal to the weight of the ball, which is:

Weight = 21.79 kg × 9.81 m/s^2

Weight = 213.68 N

So, the normal force is 213.68 N.

Now we can calculate the friction force:

Friction force = 1.45 × 213.68 N

Friction force = 309.98 N

Therefore, the force of friction between the ball and the grass is 309.98 N.

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Sampling is the process of selecting a subset of individuals or items from a larger population in order to gather information or make inferences about the whole population. This method allows researchers to collect data from a smaller group, which is more efficient and cost-effective than collecting data from the entire population.

Sampling is a crucial process in research because it helps ensure that the data collected is representative of the population and reduces the potential for bias. There are several types of sampling methods, including random sampling, stratified sampling, and convenience sampling. The choice of sampling method depends on the research question, the population being studied, and the resources available to the researcher. The accuracy of the data obtained from a sample depends on the sample size and the sampling method used. A larger sample size is generally more representative of the population and reduces the margin of error, while a smaller sample size may be more susceptible to sampling bias.

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After hitting, the two putty blobs that were locked together moved at a speed of 1.5 metres per second.

Both before and after the contact, the momentum is preserved. In other words, the starting and end momentum values are equal.

Initial momentum is 6 kg/s (kg/s = 2 * 3 + 2 * 0).

Thus, the ultimate momentum is 6 kg/m/s.

Final body weight is 2 plus 2 kg.

Final body speed is calculated as final speed/final mass, which is 6/4 = 1.5 m/s.

Thus, 1.5 m/s was the speed of the two putty blobs that had just collided and were stuck together.

Speed is defined as the ratio of distance to the amount of time it took to cover that distance. Due to its lack of magnitude and merely having a direction, speed is a scalar number.

When an item travels an identical distance in a same amount of time, this is referred to as having uniform speed.

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Answer:

zero

Explanation:

Because if the object is not in motion then it only posseses potential energy not kinetic energy

The eyes, spinal cord, and brain are all main or key parts of the nervous system.

No, the sun cannot explain global warming. Global warming is a phenomenon in which the temperature of the Earth's surface and atmosphere is rising continuously due to human activities such as deforestation, burning of fossil fuels, and industrialization.

This increase in temperature cannot be explained only by an increase in solar radiation.There are several factors which contribute to global warming, including greenhouse gases such as carbon dioxide, methane, and water vapor. These gases trap heat in the Earth's atmosphere, which causes the planet's temperature to rise. The sun's radiation does contribute to global warming, but it is not the main cause.

i) To calculate the increase in solar radiation that would cause the Earth to warm up by 1 K, we can use the following formula:ΔS = ΔT / αWhere ΔS is the increase in solar constant, ΔT is the increase in temperature, and α is the Earth's albedo (reflectivity).α = 0.30 is the standard value used for the Earth's albedo.ΔS = ΔT / αΔS = 1 K / 0.30ΔS = 3.33 W/m2So, to explain the increase in temperature of 1 K over the last hundred years, the solar constant would need to increase by 3.33 W/m2.

ii) The observed fluctuation of the solar constant over the past 400 years has been around 0.1% to 0.2%. This is much smaller than the 3.33 W/m2 required to explain the increase in temperature of 1 K over the last hundred years. Therefore, it is unlikely that the sun is the main cause of global warming.

The sun cannot explain global warming. While the sun's radiation does contribute to global warming, it is not the main cause. The main cause of global warming is human activities, particularly the burning of fossil fuels, which release large amounts of greenhouse gases into the atmosphere.

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Slab Pull  theory of plate movement relies on the weight of subducting crust.

A cold, dense oceanic plate that is falling into the mantle as a result of its own weight is said to be exerting a slab pull. According to the hypothesis, the oceanic plate sinks into the mantle because it has a higher density than the hotter mantle underneath it. Subduction is the process through which a tectonic plate descends into the mantle.

One sort of convergent boundary where two tectonic plates are clashing is a subduction zone. There may be divergent boundaries between two oceanic plates.

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I need the whole question so I can get some context.

Answer:

4200 Newtons

Explanation:

Force = mass x acceleration

1200 x 3.5 = 4200

Answer:

Compounds are two or more elements chemically combined in definite proportions by weight.

Mixtures are two or more substances not chemically combined.

Explanation:

Hope this helped Mark BRAINLIEST!!!

Answer:

A mixture can be separated by physical means

Explanation:

Answer:

here given is a weight

then force becomes mg

that is F=Mg

=4*9.8

then by using the formula

F=Ma

a=F/M

=4*9.8/9.8

=4

Explanation:

Using newtons second law

\(\\ \bull\sf\dashrightarrow Force=Mass\times Acceleration\)

\(\\ \bull\sf\dashrightarrow Acceleration=\dfrac{Force}{Mass}\)

\(\\ \bull\sf\dashrightarrow Acceleration=\dfrac{9.8}{4}\(

\(\\ \bull\sf\dashrightarrow Acceleration=2.45m/s^2\)

According to the electromagnetic spectrum, ultraviolet light has wavelengths from 10 nm to 400 nm and infrared light from 750 nm to 1 mm.

This means that infrared light has a longer wavelength than ultraviolet light.

We know the relation between wavelength and frequency as λ = c / f

where, λ is the wavelength

c is the speed of light

f is the frequency

The above equation tells us that frequency is inversely proportional to the wavelength. In other words, if the wavelength increases, frequency decreases.

As infrared light has a longer wavelength than ultraviolet light, infrared has a lower frequency than ultraviolet rays.

The question is incomplete. The complete question is how do the wavelength and frequency of infrared light compare to the wavelength and frequency of ultraviolet light?

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Answer:

30s

Explanation:

Q = charge in C(coulombs)

I = current in A(amps)

t = time in s(seconds)

Q = I × t

t = Q/I

Substitute in the given values.

t = 450C/15A = 30

t = 30s

Hope this helps! ^^

The heater was switched on for 30 seconds to allow 450 C of charge to flow through it.

To find the time the heater was switched on, we can use the equation Q = It,

where Q represents the total charge in coulombs, I is the current in amperes, and t is the time in seconds.

Given that the current (I) is 15 A and the total charge (Q) is 450 C, we can rearrange the equation to solve for time (t):

t = Q / I

Substitute the values:

t = 450 C / 15 A

t = 30 seconds

Therefore, the heater was switched on for 30 seconds to allow 450 C of charge to flow through it.

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Answer:

B

Explanation:

just took the test

Answer:

b

Explanation:

The median depth of the sinusoidal function is 14m represents the average or middle value of the water depth over one complete cycle.

To determine the period and median depth of the sinusoidal function that relates time and water depth at the ocean port, we need to analyze the given information.

The period of a sinusoidal function represents the time it takes for one complete cycle. In this case, the period would be the time it takes for the water depth to repeat its pattern.

Given that the maximum depth of 20m occurs at 8:00 am and the minimum depth of 8m occurs 6.2 hours later, we can calculate the period as follows:

Period = Time for one complete cycle = Time of minimum depth - Time of maximum depth

Period = 6.2 hours

Finally, the period of the sinusoidal function is 6.2 hours.

The median depth represents the average or middle value of the water depth over one complete cycle. To find the median depth, we can calculate the average of the maximum and minimum depths:

Median depth = (Maximum depth + Minimum depth) / 2

Median depth = (20m + 8m) / 2

Median depth = 14m

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