can someone help me asap please​

Answer:

D. crystalline solid that conducts current under certain conditions

Explanation:

Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.

Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.

Supplied energy=300kJ

Used energy:-

[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]

We know

[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]

[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]

[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]

[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]

The overall efficiency of the electric car = 76.5 %

To find the efficiency the given values are:

Energy supplied = 300 kJ

Energy wasted = 70.5 kJ

      In the system the output energy is compared to the input energy is known as efficiency. That can be written as percentage ratio of output energy to the input energy.

Formula of efficiency is,

             Efficiency = ( E out / E in ) × 100

Here, Energy supplied = 300 kJ

so, energy used = Energy supplied - Energy wasted

                           = 300 - 70.5

                           =  229.5 kJ

Thus, substituting E out = 300 kJ , E in = 229.5 kJ

            Efficiency = ( 229.5 / 300 ) ×100

                             = 229.5 / 3

                             = 76.5

Hence, The overall efficiency of the electric car is 76.5 %

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Answer:

an example of when friction is a hindrance, is if someone with shorts is sliding down a slide. their skin rubbing on the slide will cause friction and will slow them down. another example is if you're dragging a large wooden box across the floor. the wood and the floor interacting cause friction and will make it more difficult to push the box.

Explanation:

hope this helps :D

The points are

(1,10)

(6,0)

[tex]\boxed{\sf slope(m)=\dfrac{y_2-y_1}{x_2-x_1}}[/tex]

[tex]\\ \sf\longmapsto m=\dfrac{0-10}{6-1}[/tex]

[tex]\\ \sf\longmapsto m=\dfrac{-10}{5}[/tex]

[tex]\\ \sf\longmapsto m=-2[/tex]

Answer:

3.125J

Explanation:

K.E.= 1/2(mass)(velocity)^2

K.E.=1/2(0.25)(5)^2=3.125

One of the scientist's jobs is to report the results of his experiments to all the other scientists in the world.

There isn't a single real science shop anywhere in the world that uses the US customary system of units. Not one.

Even in the measly three countries that use it for measuring carpet, pumping gas, and weighing fish ... Myanmar, Liberia, an the USA ... the scientists do their work in the SI/MKS/metric system.

Answer:

78.34

Explanation:

1.3/30=78.3m

Answer:

v = 26.54 m/s

Explanation:

Given that,

The mass of a hockey puck, m = 0.21 kg

The kinetic energy of the hockey puck, E= 74 J

We need to find the speed of the hockey puck. Let the speed is v. We know that, the kinetic energy is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

Where

v is the speed

So,

[tex]v=\sqrt{\dfrac{2E}{m}} \\\\v=\sqrt{\dfrac{2\times 74}{0.21}} \\\\v=26.54\ m/s[/tex]

So, the speed of the hockey puck is 26.54 m/s.

Answer:

Mass, m = 146.72 kilograms

Explanation:

Given the following data;

Kinetic energy = 190 J

Velocity = 2.59 m/s

To find the combined mass of the girl and her bike;

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

K.E = ½mv²

Where;

K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

190 = ½*m*2.59

Cross-multiplying, we have:

380 = 2.59m

Mass, m = 380/2.59

Mass, m = 146.72 kilograms

Answer:

option C

Explanation:

Final velocity of the object is 114 m / s. Hence, final velocity of the object is 114 m / s.

Answer:

you would be paying $1845.26

Answer:

is that rm in you profile pic

Answer:

pluto

Explanation:

Dwarf because it is very minut

Answer:

I think Saturn.

Explanation:

I think the inner planets are Mercury, Venus, Earth and Mars whereas the outer ones are Jupiter, Saturn, Uranus and Neptune.

Answer:

increase

Explanation:

please mark as brainlyest

Answer

A.Increses

Explanation:

Answer:

Unconscious wish fulfillment

Explanation:

Unconscious wish fulfillment

(In the unconscious wish fulfillment theory, the actual wishes of the dreamer that are threatening to the dreamer's conscious awareness are disguised.)

Explanation:

Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. An example of measurement is 15" by 25". ... The dimension, quantity, or capacity determined by measuring.

Measurement refers to the comparison of unknown physical quantity with a known quantity.

for eg. measurement of body while sewing clothes.......

Answer:

11760 J

Explanation:

cuz potential engery is PE = MHG

SO 80×15×9.8= 11760 J

Answer:

11769j

Explanation:

here,

mass(m)=80 kg

height(h)=15m

acceleration due to gravity(g)=9.8m/s^2

now,

potential energy = m×g×h

= 80×9.8×15

= 11760j

Answer:

option b is correct..................

F = m · g

m = 1485 kg

g = 10 N/kg

F = 1485 kg · 10 N/kg = 14 850 N = 14,85 kN

Answer: The weight on Earth is 14,85 kN.

Answer:

2.5 m/s²

Explanation:

The given parameters are;

The mass of the car, m = 2,000 kg

The radius of the car, r = 40.0 m

The coefficient of friction between the car tires and the road, μ = 0.500

The constant speed with which the car moves, v = 10.0 m/s

The normal reaction of the road on the car, N = The weight of the car;

∴ N = m × g

Where;

g = The acceleration due to gravity ≈ 9.81 m/s²

N ≈ 2,000 kg × 9.81 m/s² = 19,620 N

The frictional force, [tex]F_f[/tex] = μ × N

The centripetal force, [tex]F_c[/tex] = m·v²/r

The car moves without slipping when [tex]F_f[/tex] = [tex]F_c[/tex]

Therefore, [tex]F_f[/tex] = 0.500 × 19,620 N = 2,000 kg × [tex]v_{max}[/tex]²/40.0 m

∴ [tex]v_{max}[/tex] = √(0.500 × 19,620 N × 40.0 m/2,000 kg) ≈ 14.007 m/s

Therefore, the velocity with which the car moves, v < [tex]v_{max}[/tex]

The cars centripetal acceleration, [tex]a_c[/tex] = v²/r

∴ [tex]a_c[/tex] = (10.0 m/s)²/40.0 m = 2.5 m/s²

The cars centripetal acceleration as it goes round the turn, [tex]a_c[/tex] = 2.5 m/s².

Answer:

The road surface is always rough, so the frictional force between the tires and the road surface make it difficult to maintain constant speed because acceleration always changes.

Thrust is force

Using Newtons Second law

[tex]\boxed{\sf Force=Mass\times Acceleration}[/tex]

[tex]\\ \qquad\quad\sf{:}\dashrightarrow Thrust=2(9.8)[/tex]

[tex]\\ \qquad\quad\sf{:}\dashrightarrow Thrust=19.6N[/tex]

We have that the the upthrust on a object immersed in water is

[tex]U=19.6N[/tex]

From the Question we are told that

mass= 2kg

Gravity g=9.8m/s^2

Generally the equation for the upthrust  is mathematically given as

[tex]U=mg[/tex]

Therefore

[tex]U=2*9.8[/tex]

[tex]U=19.6N[/tex]

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Explanation:

first answer is that the to and fro movement of a pendulum is known as amplitude

Answer:

334m/s

Explanation:

If you take the data you gave and insert it into the equation f=v/λ the frequency would come out to be 3.34m

334 m/s is  the Velocity of sound in air.

Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction.

The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.

Mathematically , v=fλ

According to the question,

Sound frequency (f)  = 100Hz

Wavelength (λ)= 3.34m

Computing the values in the formula,

v=fλ

v = 100Hz x 3.34m

v= 334m/s

Therefore,

Velocity of sound in air is 334 m/s.

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Answer:

a. the index of refraction for air is slightly larger for blue than for red

Answer:

Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar

Explanation: