Just need the answer to D please

Answer:

Solar panels have increased in efficiency over the past 20 years

Explanation:

Because if efficiency have increased other technologies will be discovered

Answer:

Solar panels have increased in efficiency over the past 20 years

Explanation:

Answer:the answer is B

Explanation:

APE X

The technology that is based on the work of Subrahmanyan Chandrasekhar is an orbiting observatory to detect X-rays from space objects, therefore the correct option is B.

Chandrasekhar's limit is a type of maximum limited value that is used to define the maximum mass of a white dwarf star. The generally internationally considered value of the Chandrasekhar limit is about 1.44 times the mass of the sun which is approximately 2.765×10³⁰ kg.

In other words, one can say that Chandrasekhar limit is the maximum value that can attain 1.44 times the solar mass.

In other words, one can say that star with a mass more than 1.44 times that of the Sun does not form a white dwarf but  continues to collapse, finally forming a neutron star

An orbiting observatory to detect X-rays from space objects is based on the principle of Chandrasekhar's limit. The correct option is B.

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Answer:

b. 40m/s2

Explanation:

Acceleration is calculated by dividing velocity over time. Therefore 200m/s by 5s equals 40m/s2

Answer:

B

Explanation:

v = vo + at

200 = 0 + a*5

200 = 5a

a = 200/5 = 40 m/s²

initial velocity (vo) is 0 because it says it start from station

Answer: because of air resistance. See explanation for further details.

Explanation: Galileo performed an experiment to proof that the time of descent of two different masses is independent of time.

But in reality this is most likely not true because of air resistance and other fluid frictional effects in consideration.

If the experiment is performed in a vacuum, it will always be true that time is independent of masses of two falling objects.

Answer:

Explanation:

The force acting to the right of the body is acting in the positive x direction while the force acting to the left of the body is acting in the negative x direction.

If a force of 12N acts to the left on a body and a force of 16 N acts to the right, force acting to the left will be -12N while that acting to the right will be +16N.

The resultant force acting on the bod will be the sum of the two forces.

Resultant = -12N+16N

Resultant = 4N

The direction of the resultant force will be towards the right since the resultant is a positive value.

Answer:

Green House Effect

Explanation:

Green House Effect is the principle used in solar cookers but it can be really harmful for the Earth producing some green house gases.

Answer:

The difference between P-N junction diode and extrinsic semiconductor is the allowable direction of flow of current

The extrinsic semiconductor can allow current to flow in both directions while the P-N junction diode permits only a unidirectional flow of current

Explanation:

A semiconductor is a substance that has an intermediate conductivity between that of conductors and non conductors

Examples of semiconductors  include germanium and cadmium selenide

A semiconductor to which impurities has been added (an activity known as doping) is an extrinsic semiconductor

Based on the functioning of a semiconductor, doping result in the formation of one of two types of semiconductors including;

1) N-type semiconductor that has an extra electron and the charge carriers are electrons

2) P-type semiconductor that has one less (-e⁻) electron and holes are the charge carriers

An extrinsic semiconductor can conduct allow the flow of electricity in both ways

A P-N junction diode consists of both the P and N-type extrinsic semiconductors arranged such that current can flow in only one direction.

Therefore, the difference is that the extrinsic semiconductor can allow current flow in both directions while the P-N junction diode permits only a unidirectional flow of current.

Answer:

The gyration length or radius of gyration about an axis is the radial distance from a point which would have the same moment of inertia as the body's actual distribution of mass if the body's total mass were concentrated at a point.

Explanation:

The gyration length appears to be the distance from a point where the whole body appears to be concentrated when it rotates about the point.

The gyration length can be illustrated this way.

Suppose we have a distribution of masses m₁, m₂, m₃,..., mₙ located at points r₁, r₂, r₃,..., rₙ respectively from a point O. Their moment of inertia I about point O is

I = m₁r₁² + m₂r₂² + m₃r₃² + ... + mₙrₙ²

If M = total mass = m₁ + m₂ + m₃ + ... + mₙ

Now I = MR² where R = gyration length

MR² = m₁r₁² + m₂r₂² + m₃r₃² + ... + mₙrₙ²

R² = m₁r₁² + m₂r₂² + m₃r₃² + ... + mₙrₙ²/M

R = √[(m₁r₁² + m₂r₂² + m₃r₃² + ... + mₙrₙ²)/(m₁ + m₂ + m₃ + ... + mₙ)]

R = √(∑mr²/∑m)

If the particles have the same mass, m₁ = m₂ = m₃ = ... = mₙ and M = nm. Since m = M/n

R = √[(mr₁² + mr₂² + mr₃² + ... + mrₙ²)/(m + m + m + ... + m)]

R = √[m(r₁² + r₂² + r₃² + ... + rₙ²)/nm]

R = √[(r₁² + r₂² + r₃² + ... + rₙ²)/n]

R = √(∑r²/n)

So the gyration length is the square-root of the sum of individual moment of inertias of the constituent masses divided by the sum of masses or the root mean square of the distances of the particles.

Answer:

1. Unbalanced Force (If you increase force, the acceleration will increase)

2. Mass of Body (If you increase mass, the acceleration will decrease)

Explanation:

According to Newton's Second Law the acceleration produced in a body depends upon two variables. The law states that:

“When an unbalanced force is applied on a body then an acceleration is produced in it, in its own direction”

The magnitude of produced acceleration is directly proportional to the applied force and inversely proportional to the mass of body. Mathematically,

   a α F

and,    a α 1/m

where,

a = acceleration

F = Unbalanced Force

m = Mass of Body

So, the acceleration increases when the unbalanced force increase and vice versa.

And the acceleration decreases when the mass of body increase and vice versa.

combining above equations:

a α F/m

a = (Constant)F/m

here,

Constant = 1

therefore,

F = ma

Answer:

4.29 s

Explanation:

Given:

v₀ = 0 m/s

v = 30.0 m/s

a = 7.00 m/s²

Find: t

v = at + v₀

30.0 m/s = (7.00 m/s²) t + 0 m/s

t = 4.29 s

Answer:

15 kg

Explanation:

F = m*a

F/a = m

210/14 = 15 kg

Answer:

0.71s

Explanation:

From Newton's law of motion ;

V =U +gt

V is the final velocity or speed

U is the initial velocity or speed

g is acceleration of free fall due to gravity given as 9.8m/S2

Note when a body moves horizontally down its said to do so with the aid of the force of gravity

Hence the final velocity is aided by gravity.

From the above formula;

t =V-U/ g

t= 12-5/ 9.8 = 0.71s

Answer: .71

Explanation:

Khan academy

Answer:

t = 3.01 s

Explanation:

In order to calculate how long it takes to the object to fall to the ground, you use the following formula, for the calculation of the height:

[tex]y=y_o-v_ot-\frac{1}{2}gt^2[/tex]    (1)

yo: height of the building = 105 m

vo: initial velocity of the body = 20m/s

g: gravitational acceleration = 9.8m/s^2

t: time = ?

To find the time t, you take into account that when the body arrives to the ground the height is zero, that is, y = 0.

You replace the values of all parameters in the equation (1), and you obtain a quadratic polynomial for t:

[tex]0=105-20t-\frac{1}{2}(9.8)t^2\\\\0=-4.9t^2-20t+105[/tex]

Next, you use the quadratic formula to get the roots of the polynomial:

[tex]t_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

a = -4.9

b = -20

c = 105

[tex]t_{1,2}=\frac{-(-20)\pm\sqrt{(-20)^2-4(-4.9)(105)}}{2(-4.9)}\\\\t_1=3.01s\\\\t_2=-7.09s[/tex]

You choose the positive value t1, because it has physical meanning.

Hence, the body takes 3.01s to arrive to the ground

Answer:

A resistor is a battery

Answer:

The answer is A

Explanation:

A resistor is a light bulb because it is the flow of an electric current in an electric circuit.

Answer:

1298.5watt

Explanation:

Power is defined as the rate at which work is done

Expressed mathematically as;

P = F × d/ t; F = force or weight of object ;d is height or distance sustain and t is time covered

Hence for 1 person the power consumption is ;

Note weight =mass× acceleration of free fall due to gravity,g

g is known as 9.8m/S2

Time taken is 1min which is 60 sec

60 ×9.8 × 5.3/60 = 51.94 watt

Hence for 25 persons we have

25 × 51.94 =1298.5watt

1.3kilo watt( kilo is 1000)

The work done by the escalator is 3,080.4 joules and the power requirement of the escalator to move 25 passengers every minute is approximately 51.34 watts.

The Work Done is calculated as:

Force (F) = 60 × 9.8

Distance (d) = 5.30 meters

Work (W) = F × d

Work (W) = (60 × 9.8) × 5.30

Work (W) = 3,080.4 joules

The Power is calculated as:

Time (t) = 1 minute

Power (P) = Work / Tim (t)

Power (P) = 3,080.4 / 60

Power (P) = 51.34 watts

Therefore, the power requirement of the escalator to move 25 passengers every minute is approximately 51.34 watts.

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Answer:

A ( Jack did twice as much work as Jill

Explanation:

Answer:

a) nuclear

Explanation:

Explanation:

2) C would need the least effort, because the longer the effort distance, the least the effort applied.

Answer: experimental design

the accuracy of data-collecting devices

human error

bias in selecting samples

incorrect data analysis

incorrect treatment of the control group

Explanation:

Instrumental, environmental, procedural, and human errors are frequent causes. Depending on how they affect the outcomes, each of these errors can either be random or systematic.

The discrepancy between a measured value and its true value is known as experimental error. In other words, the error or inaccuracies are what prevent us from perceiving a measurement that is 100 percent accurate.

Every measurement has some degree of experimental error, which is fairly common. Due to the widespread belief that some degree of error is inherent to the scientific method, it is not typically seen as a "mistake" in the classic sense.

However, scientists can reduce error and obtain results that are more accurate by embracing and comprehending the ways that experimental error can affect any scientific operation.

The  potential sources of error in experiment are Instrumental, environmental, procedural, and human errors.

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Answer:

636.4 J

Explanation:

The potential energy between one of the charges at the corner of the square and the fifth identical charge is U = kq²/r where q = charge = +50 × 10⁻⁶ C  and r = distance from center of square. = √2 m (since the midpoint of the sides = 1 m, so the distance from the charge at the corner to the center is thus √(1² + 1²) = √2)

Since we have four charges, the additional potential energy to move the charge to the centre of the square is U' = 4U = 4kq²/r

U' = 4kq²/r

= 4 × 9 × 10⁹ Nm²/C² (+50 × 10⁻⁶ C)²/√2 m

= 900 Nm²/√2 m

= 636.4 J

The total external energy required is 636.4 J.

According to the question, a square of side a = 2m has 4 identical charges on the corners with charge Q = 50×10⁻⁶C.

A fifth identical charge is brought at the geometric center of the square. The geometric center is at the center of the diagonal:

[tex]r=\frac{a}{\sqrt{2} }=\sqrt{2}\;m[/tex]

The potential energy is a state function which means that it depends on the initial and final position.

Now the energy required is equal to the change in potential energy

[tex]\Delta U=\frac{1}{4\pi\epsilon_o}\frac{4Q^2}{r}\\\\\Delta U=\frac{4\times9\times10^9\times(50\times10^{-6})^2}{\sqrt{2} } \\\\\Delta U=636.4\;J[/tex]

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Answer:

10.2 m/s

Explanation:

Using conservation of energy:

PE = KE

mgh = ½ mv²

v = √(2gh)

v = √(2 × 9.8 m/s² × 28.0 m × sin 11.0°)

v = 10.2 m/s

The velocity when car reaches the bottom of the hill is 10.2 m/s.

The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.

M.E = KE +PE

M.E = ½ mv² + mgh

where g is the acceleration due to gravity, v is the velocity, m is the mass and h is the height of the object.

Given is a 1380 kg car starts from rest at the top of a 28.0 m long hill inclined at 11.00 degrees.

Using conservation of energy principle, we have

PE = KE

mgh = ½ mv²

v = √(2gh)

Substitute the values, we get

v = √(2 × 9.8 m/s² × 28.0 m × sin 11.0°)

v = 10.2 m/s

Thus, the velocity when car reaches the bottom of the hill is 10.2 m/s.

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Answer:

32000 m

Explanation:

1000m in 1 km, so 32000m in 32 km.

Answer:

32000m

Explanation:

1km=1000m

so 32 kn is equals to 32000m

Answer:

frequency = wavelength over speed. f. speed = wavelength x frequency

Explanation:

it is on google

Answer:wavelength=speed/frequency

Explanation:

Given :

The frequency of travelling sound = f = 282 Hz

The speed of travelling sound = c = 343 m/s

To Find :

The distance of waves crests

Solution :

∵ wavelength of sound wave =

i.e         =

Or,        =

∴          = 1.12   m

So, The wavelength of sound wave =   = 1.21  m

Thus , The distance of waves crests =wavelength of sound wave = 1.21 m

Hence, The distance of waves crests is 1.21 meters    Answer

Answer: find the answer in the explanation

Explanation:

The capillarity of water molecules is different from the mercury molecules.

What is capillarity ?

This is the tendency of a liquid substance to rise in a capillary tube.

Molecules water rises up in a harrow tubes because of the force of adhesion between the water molecules and the tube molecules is greater than the force of cohesion between the water molecules. This helps water to wet the tube and rise. While mercury which is also a liquid falls in a narrow tubes to level below the outside surface because the force of cohesion between the mercury molecules is greater than the force of adhesion between the mercury molecules and the tube molecules. Mercury does not wet.

Answer:

[tex]v=\sqrt{\frac{ev}{m} }[/tex]

Explanation:

The helium ion has:

a potential difference in vacuum = V,

Charge = 2e

and mass = 4m,

speed = v,

mass = 4m

From electrostatics, the work done is the product of charge and its potential difference.

Therefore, Work done = charge × potential difference = 2e × V = 2eV

This work done is in form of kinetic energy, therefore:

Kinetic energy = 1/2 × mass × speed²

⇒  Work done = Kinetic energy

[tex]2eV=\frac{1}{2} *4m*v^2=2m*v^2\\v^2=\frac{2eV}{2m}\\ v^2=\frac{eV}{m}\\ v=\sqrt{\frac{ev}{m} }[/tex]

Answer:

[tex]T_{m }[/tex] = 4.86 s

[tex]T_{e}[/tex] = 1.98 s

Explanation:

Given:

Length = l = 1 m

Acceleration due to gravity of moon = [tex]g_{m}[/tex] = 1.67 m/s²

Acceleration due to gravity of Earth = [tex]g_{e}[/tex] = 10 m/s²

Required:

Time period = T = ?

Formula:

T = 2π [tex]\sqrt{\frac{l}{g} }[/tex]

Solution:

For moon

Putting the givens,

T = 2(3.14) [tex]\sqrt{\frac{1}{1.67} }[/tex]

T = 6.3 [tex]\sqrt{0.6}[/tex]

T = 6.3 × 0.77

T = 4.86 sec

For Earth,

Putting the givens

T = 2π [tex]\sqrt{\frac{1}{10} }[/tex]

T = 2(3.14) [tex]\sqrt{0.1}[/tex]

T = 6.3 × 0.32

T = 1.98 sec

Acceleration = (change in speed) / (time for the change)

Change in speed = (speed after the change) - (speed before the change)

Change in speed = (65 m/s) - (35 m/s)  =  30 m/s

Acceleration = (30 m/s) / (5 s)

Acceleration = 6 m/s²

Answer:

Its A

Explanation:

Thats because federalists wanted to take away rights. But the fathers wanted to definitely ensure that each person had equal rights and liberty.