An example of a poor conductor of electricity is a
A. paper clip
B. gold necklace
c. cup of salt water.
D.
cup of pure water.

The maximum height reached by the brick above the ground is 20 ft. The time taken by the brick to reach the ground is 0 seconds. Free-fall motion (uniformly accelerated motion) after falling from a height of 20 feet. Further, the acceleration experienced by the free brick is equal to the acceleration due to gravity which is approximately 32ft/sec², downward.

Hence, we can write its acceleration as, a = g = 32ft/sec².

Here, u = 0 as the brick was not moving initially while it was at rest on the top of the load of bricks.

Now, the value of v(t) can be obtained by integrating the above expression w.r.t. time as shown below:v(t) = u + a.t = 0 + 32t = 32t ...(1)

The value of x(t) can be obtained by integrating the expression for v(t) w.r.t. time, i.e. t as shown below :x(t) = (1/2).a.t² + u.t + x₀ = (1/2).32t² + 0 + 20ft = 16t² + 20ft ...(2)

Here, x₀ = 20ft is the initial displacement of the brick above the ground.

Now, we can answer the questions as follows:

(a) Using  the following relation: v = u + a.t = 0 when the brick is at its highest point.

Hence, the time taken to reach this point can be obtained as follows:0 = u + a.t ⇒ t = (-u/a) = (0/32) sec = 0 secThis means that the brick reaches its maximum height at t = 0 sec, which is the initial moment.

Thus, the maximum height reached by the brick above the ground is, x(0) = 16.0² + 20 = 20 ft

(b) The time taken by the brick to reach the ground can be obtained by using the following relation: x(t) = 0.

Here, we are interested in finding the value of t.

Hence, we can substitute x(t) from equation (2) above and equate it to 0 to obtain the value of t as shown below:16t² + 20 = 0 ⇒ t² = -(20/16) sec².

This means that the brick doesn't take any finite time to reach the ground from its maximum height.

This is because it falls vertically downwards from a height of 20 ft under the action of gravity.

Thus, it reaches the ground at t = 0 sec only.

(c) The speed of the brick just before it hits the ground can be obtained by using the expression for v(t) from equation (1) above and substituting t = 0 sec (just before it hits the ground) as shown below:

v(0) = 32(0) = 0 ft/sec.

Hence, the speed of the brick just before it hits the ground is 0 ft/sec.

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Answer:

Biosphere are the regions of the surface, atmosphere, and hydrosphere of the earth.

Hydrosphere is when all the waters on the earth's surface, such as lakes and seas, and sometimes including water over the earth's surface, such as clouds.

Atmosphere is the envelope of gases surrounding the earth or another planet.

Explanation:

Hope this helps you out !!!

Answer:

La vdd tengo la misma duda, de q prepa eres?

Explanation:

Nada más para saber

Electromagnetic waves are a form of radiation that occurs when electric fields and magnetic fields are coupled with each other. Thus, option C is correct.

An electromagnetic field is formed with an electric field and a magnetic field that are dependent on each other. The two fields are perpendicular to each other and travel in that direction as well.

Electromagnetic waves are not elastic waves either and can travel in a vacuum. They are different from mechanical waves as electromagnetic waves can travel in the absence of a medium. They travel at the speed of 3x\(10^{8}\)m/s. Thus, only option C is right.

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Complete question:-

Which of the following are the characteristics of electromagnetic waves?

1. They are elastic waves.

2. They can also move in a vacuum.

3, They have electric and magnetic components which are mutually perpendicular.

4, They move with a speed equal to 3 lakh meters per second.

Select the correct answer using the code given below :

A) 1, 2, 3 and 4

B) 1, 2, and 4

C) 2 and 3 only

D) 3 and 4 only

"Microwave transmission systems are used for high volume, long distance, line-of-sight communications."

Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video, and data information.

Due to their small wavelength and ability to be focused into narrow beams that may be targeted directly at the receiving antenna, microwave links are frequently employed for point-to-point communications. As opposed to lower frequency radio waves, which interfere with one other, this enables neighbouring microwave equipment to operate on the same frequencies.

Another benefit is that the microwave band has a very high information-carrying capacity due to its high frequency; its bandwidth is 30 times greater than that of the radio spectrum below it.

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Accident: Get burned

Prevention: turn off the burner.

To determine the new retained earnings as of July 31, 20rd, we can use the given information:

Retained earnings, July 1, 20rd: $259,725

Increases: Net income (Part B) = $10,325

Decreases: Dividends (Part C) = $12,000

The calculation for new retained earnings, July 31, 20rd would be:

Retained earnings, July 31, 20rd = Retained earnings, July 1, 20rd + Increases - Decreases

Retained earnings, July 31, 20rd = $259,725 + $10,325 - $12,000

Retained earnings, July 31, 20rd = $258,050

Therefore, the new retained earnings as of July 31, 20rd is $258,050.

The statement of cash flows for July would be as follows:

Statement of Cash Flows for July

Cash flows from operating activities:

Cash inflows:

Cash from customers $68,000

Cash outflows:

Payments for rent $(5,600)

Payments for supplies $(62,600)

Payments to creditors $(12,800)

Payments for utilities $(4,750)

Net cash flows from operating activities $(17,750)

Cash flows from investing activities:

Cash outflows:

Purchase of land $(150,000)

Net cash flows from investing activities $(150,000)

Net increase (decrease) in cash $(179,750)

Plus: Cash balance, July 1, 20rd $294,000

Cash balance, July 31, 20rd $114,250

Please note that the information provided assumes a cut-off date of July 31, 20rd.

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the Copernican system supported by Galileo and the evidence that Galileo used to support this view is described bellow.  

The astronomical theory postulated by Nicolaus Copernicus and published in 1543 is termed as Copernican heliocentrism theory. The Earth and the other planets orbited the Sun in a circular orbit at constant speeds, modified by epicycles, in the model's position at the center of the universe.

Galileo's observations of four moons orbiting Jupiter, that provided confirmation for Copernicus' heliocentric hypothesis. He began charting the locations of the four "Medicean stars" every night on January 7, 1610. (later renamed the Galilean moons).

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Explanation:

HELP PLS

Hang time is the time it takes to reach the peak of your jump.

False

Surfing purists dislike aerial moves in competitions, preferring traditional surfing. There is controversy over the emphasis on aerial moves, and diversity of opinion within the community.

The surfing "purists" are likely to be critical of the movement towards incorporating aerial moves into surfing competitions, as they are described as valuing "traditional" or "classic" surfing.

The text notes that these purists "feel that aerial moves represent a departure from classic surfing," and quotes a professional surfer who suggests that "real surfing is all about turns and the flow of the wave."

The article also notes that there is some controversy within the surfing community over the emphasis on aerial moves, with some feeling that it has become too dominant in competitions. This further suggests that there are those within the community who are resistant to this trend.

Overall, it seems that the surfing "purists" value a more traditional, flowing style of surfing and may view aerial moves as a departure from this style.

However, it is important to note that there is diversity of opinion within the surfing community, and not all surfers or fans may share this view.

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The efficiency of the engine is 60%.

The efficiency of a heat engine describes the amount of input energy converted into useful work.

It also entails the amount of useful work done by the engine. The greater the amount of useful work done by the engine, the greater the efficiency of the engine.

The efficiency of an engine ranges from 0 to 100%.

If there four stages in the energy conversion cycle, and 10% energy is wasted in each cycle, the total energy wasted in the four cycles is calculated as;

Total wasted energy = 4 x 10% = 40%

Efficiency of the engine = Useful energy = 100% - 40% = 60%

Thus, the efficiency of the engine is the useful work done by the engine.

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Answer:

a. 100.0 kg

Explanation:

Given parameters:

Mass  = 100kg

Force of gravity  = 2.5m/s²

Unknown:

mass on Jupiter  = ?

Solution:

The mass of a substance is the quantity of matter such body possess. Mass is the same.

So, the mass of earth and on Jupiter is the same.

Only the weight of the object will differ since weight is contingent on the force of gravity from places to places.

My mass on Jupiter will still be 100kg

The amount of helium atoms lined up side to side that  would span the diameter of a human hair is: 1.5625*10^6  atoms

To solve this problem the we have to do the conversion of units with the given information.

Information about the problem:

By converting the units of the helium atom's diameter from nm to mm, we have:

d(helium atom)= 0.064 nm * 1 m/1*10^6 mm

d(helium atom)=  6.4*10^-8 mm

To know how many helium atoms lined up side to side would span the diameter of a human hair, we have to do a division as a following:

amount of helium atoms lined up side to side= d(human hair)/d(helium atom)

amount of helium atoms lined up side to side= 0.1 mm/6.4*10^-8 mm

amount of helium atoms lined up side to side= 0.1 mm/6.4*10^-8 mm

amount of helium atoms lined up side to side= 1.5625*10^6

It is the transformation of a value expressed in one unit of measurement into an equivalent value expressed in another unit of measurement of the same nature.

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Answer:

C

Explanation:

The force exerted by air as an object moves through it requires contact. Hence, option (C) is correct.

Any force that develops as a result of two objects coming into touch with one another is referred to as a contact force. The majority of the observable interactions between macroscopic groupings of matter are caused by contact forces, which are pervasive. Some commonplace instances of contact forces in action include pushing a car or kicking a ball. A person constantly applies force to the car in the first scenario, whereas a small impulse is used in the second.

Ordinarily, contact forces are divided into two orthogonal parts: the normal force, which is perpendicular to the surface(s) in contact, and the friction force, which is parallel to the surface(s). Here the force exerted by air as an object moves through it requires contact.

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High-frequency rTMS and low-frequency rTMS are believed to stimulate and inhibit, respectively, activity within those brain regions to which it is applied.

rTMS stands for Repetitive transcranial magnetic stimulation.

It is a safe, harmless and non-invasive method that is used to treat brain activities by controlling the brain stimuli.

Depressed and anxious patients suffer from brain diseases and exhibit different levels of brain activities leading to the release of stimuli in high and low amounts.

However, it is a widely used technique that is differentiated into high and low-frequency rTMS.

Low-frequency rTMS has a value of less than 1 Hz and exhibits inhibitory effects while high-frequency value exceeds 5 Hz and exhibits excitatory effects.

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The statement is true. The abdominal oblique muscles does compress the abdomen.

The abdominal oblique muscles are responsible for compressing the abdomen, along with other muscles in the abdominal wall. When contracted, these muscles help to increase intra-abdominal pressure, which is important for various bodily functions such as breathing and digestion.

The abdominal oblique muscles are situated on the lateral side of the abdomen. It is the largest abdominal muscle.

The abdominal oblique muscles do compress the abdomen. stabilizing the core, as well as aiding in various movements and providing compression to the abdominal area.

An abdomen consists of stomach, intestine ,pancreas ,liver, gall bladder etc. It is situated between chest and the pelvic area.

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Answer:

Three laws

Explanation:

Three laws of motion that Newtown developed.

The current in a coil with a 703702 density of turns, that had a 416 x10⁻³ t magnetic field is approximately 2.10 x 10⁻⁷ A.

Current flowing through the circuit has a direct relationship with the magnetic field strength. Every time an electric current is present, a magnetic field is created that is always perpendicular to the passage of the current.B and H represent the magnetic field. Amperes per metre (A/M) and Newtons per metre per ampere (N/M/A) or Teslas are the SI units for H and B, respectively.

we know that

I = B * r / (μ_0 * N * k)

μ_0 = 4π x 10⁻⁷ T·m/A

k=703702 density of turns

now we have,

I / A = 0.148 / (k * turns/m²)

I / A = 0.148 / (703702 )

I = A * (0.148 / 703702)

I = 2.10 x 10⁻⁷ turns/m²

Therefore, current in the coil is approximately 2.10 x 10⁻⁷ A.

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Answer:

1) Given acceleration due to gravity as 10N/kg

N/kg is the same as m/s². From W=mg

making g subject ... you have g = W/m

where m is in kg and W is in N

hence we have N/kg

So g=10ms-²

Gravitational Potential Energy=mgh

At height 4m

PE=6 x 10 x 4

=240J.

At height 6m

PE=6 x 10 x 6

=360J.

2) KE=1/2mv²

=1/2 x 6 x 5² =75J

When the speed is doubled... it becomes 2x

so V = 2x5=10ms-¹

KE=1/2 x 6 x 10² =300J.

3) KE=1/2mv²

KE is given as 100J

mass=0.5kg

Making V the subject

you have v² =2KE/m

v²=2 x 100/0.5

v²=400

taking square root

v=20ms-¹.

Have a great day✌

Answer:

Explanation:

g means gravitation

G is universal gravitational constant

M = mass of the earth

R = radius of the earth

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The hare can afford to nap for a maximum time of 6.67 seconds without losing the race if his speed is 15 m/s.

After running for 7 seconds, the hare has covered a distance of:

\(d_h = v_h * t = 15 m/s * 7 s = 105 m\)

The hare is now 895 m away from the starting line and 100 m away from the finish line. The tortoise is 895 m away from the starting line and moving towards the finish line at a speed of 0.27 m/s.

The hare needs to cover a distance of 100 m to reach the finish line, while the tortoise needs to cover a distance of 895 m. If the hare takes a nap for a certain amount of time, the tortoise will continue to move towards the finish line and may eventually cross the finish line before the hare wakes up.

We can calculate the time it would take the tortoise to reach the finish line by dividing the distance by its speed:

\(t_t = d_t / v_t = 895 m / 0.27 m/s = 3314 s\)

The hare needs to wake up and cover the remaining distance to the finish line before the tortoise does. The distance the hare needs to cover is:

\(d_h = 100 m\)

The maximum speed of the hare is 15 m/s, which means the time it would take the hare to cover the distance is:

\(t_h = d_h / v_h = 100 m / 15 m/s = 6.67 s\)

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The star is in energy balance when its core energy production matches the amount of energy it radiates into space. This is only true when the star is a main-sequence star with a hydrogen core fusion and when it is a helium core-fusion star. It is out of energy balance at all other times, which is why it is either contracting or expanding.

Stars can squeeze various types of atomic fuel together, and it's through this process that we get almost every element in the universe. Stars contain a lot of mass which has a lot of gravity. The gravity pulls inwards, which could cause a star to collapse in on itself. In a main sequence star, this inward pull is balanced by the outward gas pressure due to the nuclear fusion reactions deep in the star's core. This balance is called hydrostatic equilibrium and stops the main sequence stars from collapsing.

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Answer:

\(30\; {\rm m\cdot s^{-1}}\).

Explanation:

Since acceleration stays the same, Apply the SUVAT equation \(v^{2} - u^{2} = 2\, a\, x\), where:

Rearrange this equation to find \(v\), velocity of the plane after accelerating:

\(v^{2} = u^{2} + 2\, a\, x\).

\(\begin{aligned} v &= \sqrt{u^{2} + 2\, a\, x} \\ &= \sqrt{(8)^{2} + 2\, (2)\, (209)}\; {\rm m\cdot s^{-1}} \\ &= \sqrt{900}\; {\rm m\cdot s^{-1}} \\ &= 30\; {\rm m\cdot s^{-1}}\end{aligned}\).

The work done by the force is approximately -12.1 J.

The work done by a constant force is given by the equation W = F . d, where F is the force vector, d is the displacement vector, and "." represents the dot product. The displacement of the particle is given by the vector r, so we can calculate the work done as follows:

W = F . d = (3.39i + 4.72j) N . (1.85i - 2.51j) m

= (3.39 x 1.85 + 4.72 x (-2.51)) J

= -12.1 J (to two decimal places)

The speed of the particle at position r can be calculated using the conservation of energy principle. Since no external work is done on the system (i.e., the net work is zero), the initial kinetic energy of the particle is equal to its final kinetic energy plus its change in potential energy. We can solve for the final speed as follows:

Initial kinetic energy = 1/2 mv^2 = 1/2 x 3.51 kg x (4.51 m/s)^2 = 35.8 J

Final kinetic energy = 1/2 mv^2 (where v is the final speed)

Change in potential energy = -W = 12.1 J (from above)

Therefore, 35.8 J = 1/2 x 3.51 kg x v^2 + 12.1 J, which gives v = 5.17 m/s (to two decimal places).

The change in potential energy of the system is equal to the negative of the work done by the force, so it is approximately 12.1 J (as calculated above).

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Answer: 48 km/hr

Explanation:

speed= distance/time

144/3

=48 km/hr

The modulus of elasticity, E, is a measure of a material's stiffness and ability to resist deformation when a force is applied. It is defined as the ratio of stress to strain within the elastic range of the material. In other words, it describes how much a material will stretch or compress under a given force.

The modulus of elasticity is important because it allows engineers to predict how materials will behave under different conditions, such as temperature changes, loading conditions, and other factors. It also helps to determine the maximum load a material can withstand before it starts to deform or break.

In detail, the modulus of elasticity is a fundamental property of a material that describes its ability to resist deformation when subjected to external forces. It is calculated by measuring the stress and strain of the material and using the equation E = σ/ε, where σ is stress and ε is strain.

The modulus of elasticity is important in many areas of engineering, such as structural design, materials science, and mechanics. It helps to ensure that structures and materials are designed and tested to withstand the loads and stresses they will be subjected to, and it provides a basis for comparing different materials and choosing the best one for a particular application.

In summary, the modulus of elasticity, E, is a material property that describes its stiffness and resistance to deformation. It is correctly determined using Hooke's Law and is crucial for predicting the mechanical behavior of materials when subjected to stress.

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The ball rolled for 13.2 s

Speed is scalar and no direction

\(\tt avg~speed=\dfrac{total~distance}{elapsed~time}=\dfrac{\Delta x}{\Delta t}\)

A bowling ball rolls 33 m, with average speed = 2.5 m/s

So elapsed time :

\(\tt t=\dfrac{33~m}{2.5`m/s}=13.2~s\)

Answer:

13.2

Explanation:

Answer:

30 mph

Explanation:

False. A more massive star does not have a smaller habitability zone than a smaller star.

In fact, the habitability zone of a star, also known as the "Goldilocks zone," refers to the region around a star where conditions are just right for the existence of liquid water on the surface of a planet. This zone is determined by the star's luminosity and its distance from the star.

The habitability zone of a star depends on its luminosity, which is directly related to its mass. More massive stars have higher luminosities and emit more energy compared to smaller stars. As a result, the habitability zone of a more massive star is actually larger, extending farther out from the star, than that of a smaller star.

This is because a more massive star has a higher energy output, which means it can support a habitable zone at a greater distance. On the other hand, smaller stars have lower luminosities and emit less energy, resulting in a habitability zone that is closer to the star.

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