why is SI unit established


Answers

Answer 1

Explanation:

The SI was established in 1960 by the 11th General Conference on Weights and Measures (CGPM, Conférence Générale des Poids et Mesures). The CGPM is the international authority that ensures wide dissemination of the SI and modifies the SI as necessary to reflect the latest advances in science and technology.


Related Questions

Scientists have invented the equipment to harness the power of lighting for energy use. True or false

Answers

I think it’s false .
Let me know if it’s incorrect .

How much time will it take for a truck to travel 20 meters if it is traveling at 4 m/s?

Answers

Answer:

The answer is 5 s

Explanation:

The time taken can be found by using the formula

[tex]t = \frac{d}{v} \\ [/tex]

d is the distance

v is the velocity

From the question we have

[tex]t = \frac{20}{4} \\ [/tex]

We have the final answer as

5 s

Hope this helps you

the answer to this question is 5s

what does terminal velocity mean ? please help

Answers

[tex] \underline{ \bf{\underline{\large{Terminal \: Velocity}}}}[/tex]

The maximum constant velocity acquired by a body while falling through a viscous medium is called it's terminal velocity. It is usually denoted by [tex] \sf V_T [/tex].It is directly proportional to the square of the radius of the body (a²) & the difference of the densities of the body and the fluid [tex] \sf (\rho - \sigma) [/tex].It is inversely proportional to the viscosity of the medium [tex] \sf (\eta) [/tex].Formula of Terminal Velocity:[tex] \boxed{ \bf{V_T = \dfrac{2}{9} \dfrac{ {a}^{2} }{ \eta} ( \rho - \sigma)g}}[/tex]
Terminal velocity means steady speed achieved.

PLZ HELP ME

1. A stone is thrown horizontally from a cliff 30m high with an initial speed of 20m/s. How far from the cliff does the stone strike the ground?


2. A ball rolls off the edge of a table 1.44m above the floor and strikes the floor at a point 2m horizontally from the edge of the table.

A) What is the time the ball was in the air?


B) What is the initial velocity of the ball?



3. A golfer hits a ball and gives it an initial velocity of 40 m/s, at an angle of 30º above the horizontal.

A) How long does the ball stay in the air?


B) How far horizontally (the range) does the ball travel before hitting the ground?

Answers

Answer:

1. The stone will strike the ground 49.46 m from the base of the cliff

2. A) Approximately 0.542 seconds

B)  Approximately 3.69 m/s

3. A) The time the ball spends in the air is approximately 4.0775 s

B) The horizontal range is approximately  141.25 m.

Explanation:

1. The time it takes the stone to land is given by the equation, t = √(h/(1/2 × g)

∴ t = √(30/(1/2 × 9.81)) ≈ 2.473 seconds

The horizontal distance covered by the stone in that time = 20 × 2.473 ≈ 49.46 m

The stone will strike the ground 49.46 m from the base of the cliff

2. A) The time the ball spends in the air = t = √(h/(1/2 × g)

∴ t = √(1.44/(1/2 × 9.81)) ≈ 0.542 seconds

B) The initial horizontal velocity, u = Horizontal distance/(Time) = 2/0.542 ≈ 3.69 m/s

The initial horizontal velocity ≈ 3.69 m/s

3. A) The time the ball spends in the air is given by the following equation;

t = 2 × u × sin(θ)/g = 2 × 40 × sin(30)/9.81 ≈ 4.0775 s

t ≈ 4.0775 s

B) The horizontal range, R, of the  ball is given by the equation for the range of a projectile as follows;

[tex]Range, R = \dfrac{u^2 \times sin (2 \cdot \theta) }{g}[/tex]

Substituting the known values, gives;

[tex]Range, R = \dfrac{40^2 \times sin (2 \times 30^{\circ}) }{9.81} \approx 141.25 \ m[/tex]

The horizontal range ≈ 141.25 m.

A rocket ship is moving through space at 1200 m/s. The rocket ship accelerates at a rate of 4 m/s in the same direction. What is the rocket ship's speed after 200 seconds of acceleration?

Answers

Answer:

Vf = 2000 [m/s]

Explanation:

To solve this problem we must use the following equation of kinematics.

[tex]v_{f} =v_{o}+a*t\\[/tex]

where:

Vf = final velocity [m/s]

Vo = initial velocity = 1200 [m/s]

a = acceleration = 4 [m/s]

t = 200 [s]

Vf = 1200 + (4*200)

Vf = 1200 + 800

Vf = 2000 [m/s]

Ashley is flying a plane that has to reach a gradient of 360m/km in order to take off and not crash. Her goal is to travel from sea level to an elevation of 1000m at a distance of 2.8km. Calculate the gradient of Ashley’s flight and determine if she will crash!

Answers

Answer:

She is likely to crash because her flight gradient is lesser than the flight gradient required gradient to avoid crashing

Explanation:

The given parameters are;

The required gradient of the plane Ashley is flying needs to reach in order to take off and not crash = 360 m/km

The initial elevation of the plane Ashley is flying = Sea level = 0 m

The goal Ashley intends to make = Elevation of 1000 m at 2.8 km. distance

∴ Ashley's goal = Traveling from sea level to 1000 m at 2.8 km horizontal distance

We have;

The gradient  = Rate of change of elevation/(Horizontal distance)

Therefore;

The gradient of Ashley's flight = (1000 - 0)/(2.8 - 0) = 357.143 m/km

The gradient of Ashley's flight ≈ 357.143 m/km which is lesser than the required 360 m/km in order to take off and not crash, therefore, she will crash.

400 N of load can be overcome by an effort of 50 N by using a lever. Calculate the mechanical advantage of the lever.

Answers

Answer:

load (l)=400N

Effort(E)=50N

mechanical advantage (MA)= load ÷Effort

(ma)=400÷50

(ma)=8

Explanation:

I copy pasted from the answer from the same question. Remember to first check if ur question is there

Which arrow represents the centripetal acceleration?

Answers

Answer:

x

Explanation:

because the force on the car by gravity adds speed and acceleration.

A satellite was in two separate crashes. In both crashes, the satellite had the same mass. Engineers want to know about the speed and direction of the satellite after the crashes. Why would the crash affect the motion of the satellite, and which crash caused a greater change in motion for the satellite?

Answers

Answer & Explanation:

Crashing into the asteroid would cause the satellite to slow down, stop, or reverse direction, because it is a force in the opposite direction to the satellite's motion. Whichever crash was a stronger force would cause it to change motion more. It takes a stronger force to change the velocity of a more massive object.

A 30 kg object has a frictional force of 60 N. It's coefficient of friction must be...?
A) 0.2
B) 2
C) .002
D) 20

Answers

mass = 30kg

frictional force = coefficient of friction * (mass * g)

g = 9.8 m/s^2

So:

60N = x * 294 N

x = 60 N / 294 N = 0,2

Explain how bar graphs can show comparisons between 2 topics.

Answers

Answer:

A bar chart is typically used for the comparison of informations obtained from a data collection by representing each value (information) with rectangular bars respectively.

Explanation:

A bar chart also known as a bar graph can be defined as the graphical representation of data (informations) by using vertical columns or rectangular bars. When a data set is observed, a bar chart can be used to graphically represent or record the total or overall amount of information contained therein. Generally, bar charts are used for the comparison of informations obtained from a data collection by representing each value (information) with rectangular bars respectively.

The bar graph has a x-axis and a y-axis used to represent the various categories of data collected.

In this scenario, the x-axis is used to denote the points earned by the teams while the y-axis is used to denote the seasons as seen in the image attached.

Hence, point scores by team (Team A, B and C) per seasons (2002, 2003, 2004 and 2005) can best be compared through the use of a bar chart (graph).

Answer:

Answer above is correct i only put this:

Explanation:

A bar chart is typically used for the comparison of informations obtained from a data collection by representing each value (information) with rectangular bars respectively.

Which Box in the diagram above, should this picture go into?
Box A
ООО
O Box B
O Box C



Plzz answerr idk

Answers

What diagram? There isn’t one

The space shuttle design team spent two years working with sketches and models before building the shuttle. Why were these steps important?



1.Sketches and models allowed for the design to be modified before investing huge amounts of time and money to build the actual shuttle.

2.Sketches and models allowed for many different astronauts to provide input on the design of the shuttle before investing money in the actual shuttle.

3.Sketches and models helped astronauts in their training program as they prepared for their missions.

Answers

Answer:

sketches and models helped astronauts in their training program as they prepare for their missions

Given that on the moon g = 1.6 m/s2, and on Earth g = 9.8 m/s2, if a car on the moon weighs 3.8 N, what is its mass on Earth?

Do not write units in your answer, only numbers.

Round to one decimal place.

Answers

Answer:

The weight of the car on Earth is 19.6

Explanation:

The given parameters are;

The gravitational acceleration on the moon, [tex]a_{Moon}[/tex] = 1.6 m/s²

The gravitational acceleration on Earth, g = 9.8 m/s²

The weight of the car on the moon = 3.8 N

The weight of an object = The mass of the object, m × The gravitational acceleration acting on the object, g

The weight of the car = The mass of the car × The gravitational acceleration on the moon

∴ 3.8 N = The mass of the car × 1.6

The mass of the car = 3.8/1.6 = 2 kg

The weight of the car on Earth =The mass of the car × The gravitational acceleration on Earth, g

The weight of the car on Earth = 2 × 9.8 = 19.6

The weight of the car on Earth = 19.6.

Plyometrics can help a person maintain cardiorespiratory fitness. Please select the best answer from the choices provided. T F

Answers

Answer: IT IS TRUE

Explanation:

Hope this helps

Plyometrics can help a person maintain cardiorespiratory fitness T

It is TRUE that plyometrics can help a person maintain cardiorespiratory fitness

Plyometrics

Plyometrics is a type of exercise training that works with the principle of using speed and force of different movements to build muscle power.

Plyometrics include different types of exercises such as pushups, throwing, running, jumping, and kicking.

Learn more about plypmetrics:

https://brainly.com/question/1526420

hey pls help with this HDJSJDH im rlly bad at this kinda stuff :,) i'll mark the correct answer brainliest

Answers

I am pretty sure it’s A
The cue exerts force onto the white ball which pushes the blue ball into the direction of the hole.

Answer:

A. Cue, White Ball, Blue Ball

Explanation:

Visualize in which order things are being hit

1. In your own words explain what happens at a subduction zone. 2. In your own words explain what happens at a mid-ocean ridge. 3. At a subduction zone what causes magma to rise?

Answers

Answer:

1. The subduction zone serves as the meeting point for two tectonic plates.

2. At the Mid- Ocean ridge, decompression melting occurs.

3 What causes the magma to rise is the increase in pressure caused by collection of gases by the magma.

Explanation:

Subduction zone is define as a zone where tectonic plates ( an oceanic plate slides beneath a continental plate) meets and contributes to the rise of magma to the surface in geological sciences.

At the Mid - Oceanic ridge, decompression melting occurs. As mantle ascends beneath the mid-ocean ridge, less and less rock lies above it, so large pressure changes occur, which leads to melting. The melt is less dense than the solid, and rises to the surface to form the oceanic crust.

At the subduction zone the magma that is formed is usually made up of silica rich lava. Thick silica rich magma does not release the gasses very easily so they build up inside the magma chamber. As the gasses collect in the chamber, the pressure rises. It is possible for the pressure to rise so much that the chamber cannot contain the magma and it erupts explosively.

in the movie "gravity" - Why did the escape pod get stuck and pulled back?

Answers

Answer:

because nono gravity

Explanation:

no gravity

Bc there no gravity so thtas why it won’t

A fire is burning in a fireplace. Where is the radiation?

A. You touch warm bricks next to the fireplace
B. You can feel the heat from across the room
C. Heat is rising up from the chimney

Answers

I think it’s A.
........

Jen had an average speed of 2.5 m/s when hopping on one foot. If she hopped for 5.0 seconds, for what distance was she hopping?

Answers

Explanation:

distance

speed =_________

time

distance = speed × time

= 2.5 × 5.0

distance = 12.5 m

find acceleration of block and tension in strings if m1 =8kg m2= 4kg and take g=10m/s²​

Answers

[tex]\large\bold{\underline{\underline{Given:-}}}[/tex]

[tex]\sf{m_1}[/tex] = 8kg

[tex]\sf{m_2}[/tex] = 4kg

g = 10m/s²

[tex]\large\bold{\underline{\underline{To \: Find:-}}}[/tex]

→Acceleration of block

→Tension in strings

[tex]\large\bold{\underline{\underline{Solution:-}}}[/tex]

Let, the two equation will be ,

[tex]\leadsto[/tex] 8g - T = 8a ..... Equation no (1)

[tex]\leadsto[/tex] T - 4g = 4a ..... Equation no (2)

Putting the value of equation no (1) and (2) we get,

[tex]\implies[/tex] 4g = 12a

[tex]\implies[/tex] 4 × 10 = 12a

[tex]\implies[/tex] 40 = 12a

[tex]\implies[/tex] a = [tex]\sf\dfrac{\cancel{40}}{\cancel{12}}[/tex]

[tex]\dashrightarrow[/tex] a = [tex]\dfrac{10}{3}[/tex]

Again, we have to putting the value of a in the equation no (2) we get,

[tex]\implies[/tex] T - 4g = 4 × [tex]\dfrac{10}{3}[/tex]

[tex]\implies[/tex] T - 4 × 10 = 4 × [tex]\dfrac{10}{3}[/tex]

[tex]\implies[/tex] T - 40 = [tex]\dfrac{40}{3}[/tex]

[tex]\implies[/tex] T = [tex]\dfrac{40}{3}[/tex] + 40

[tex]\implies[/tex] T = [tex]\dfrac{40 + 120}{3}[/tex]

[tex]\dashrightarrow[/tex] T = [tex]\dfrac{160}{3}[/tex] N

[tex]\therefore[/tex] Acceleration of block = [tex]\dfrac{10}{3}[/tex] m/s².

And, Tension in strings = [tex]\dfrac{160}{3}[/tex] N

PLZ EXPLAIN THE EQUATION AND I WILL GIVE BRAINLIST You are out and about in the country and your father sees a rock that he really wants in the yard. Now you must get the very heavy rock into the back of a truck. The truck bed is 3 feet off the ground. Your father pulls out a 5-foot plank and begins to set up a ramp. At the same time, you (who know about mechanical advantage!) have found a plank that is 8 feet long, and you show it to your father. Which plank will give you the most mechanical advantage? Calculate the MA for each plank

Answers

Answer:

The 8 foot long plank

Explanation: hope this helps :)

When the energy of a wave increases, what happens to the amplitude?

Answers

Answer:

The energy transported by a wave is directly proportional to the square of the amplitude. So whatever change occurs in the amplitude, the square of that effect impacts the energy. This means that a doubling of the amplitude results in a quadrupling of the energy.

Explanation:

When the energy of a wave increases, the amplitude also increases. This is because the amplitude of the wave is directly proportional to the energy of a wave.

What is the amplitude of a wave?

The amplitude of a wave may be defined as the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of the vibration path.

It is the principle of physics that when the amplitude of the wave is higher, the energy also gets higher. To summarise, waves carry energy. The amount of energy they carry is related to their frequency and their amplitude. The higher the frequency, the more energy, and the higher the amplitude, the more energy.

Therefore, when the energy of a wave increases, the amplitude also increases. This is because the amplitude of the wave is directly proportional to the energy of a wave.

To learn more about Energy and amplitude, refer to the link:

https://brainly.com/question/19036728

#SPJ6

43
Select the correct answer.
According to the law of reflection, what is the relationship between the angle of incidence and the angle of reflection?
OA. The angle of reflection is twice the angle of incidence.
OB.
The angle of reflection is half the angle of incidence.
OC. The angle of reflection is equal to the angle of incidence.
OD. The angle of reflection is independent of the angle of incidence.
ОЕ.
The angle of reflection is always perpendicular to the angle of reflection.
Reset
Next

Answers

Answer is c, they are equal:

Explanation:

the person is not able to see the far lying object clearly. which type of lens will the doctor prescribe him give reason?

Answers

Answer:

correction of farsightedness uses a converging lenses that compensates for the under convergence by the eye. the converging lens produces an image farther from the eye than the object so that farsighted can see it clearly.

to calculatw the power produced by a force, the size of the force must be known. What else needs to be known to calculate the power

Answers

-- The distance the force moved through

-- How long the force lasted

The other thing we need to calculate the power is the "Velocity".

A quantity of labor or work done to be accomplished within a particular period of timeframe is determined as power. It is denoted by "P".According to the given query, we are talking about the relation between Power and Force. Along with simple instances where such an item is moved at continuous speed by a constant force.

The relation can be shown as:

→ [tex]P= Fv[/tex]

where,

P = PowerF = Forcev = Velocity

Thus the above is the right response.

Learn more about Power here:

https://brainly.com/question/11380506

What is the density of water?
gram/mL
(fill in the number)

Answers

Answer:

1.00 gram per milliliter (1 g/mL). In other words, 1 milliliter of water has a mass of 1 gram. A drop of water is 0.05 mL of water, so its mass would be 0.05 grams.

Explanation:

What are greenhouse gases? Can you name any?

Answers

greenhouse gasses in the upper atmosphere trap heat from the Earth and reflect it back down rather than allow it to escape. This makes Earth progressively warmer.

A rock falls off a cliff that is 82 m high. How fast is the rock moving when it hits the ground?

Answers

Answer:

40.1m/s

Explanation:

This is a kinematics problem

x = 82m

a = -9.8m/s^2

v(initial) = 0

Find: v(final)

Using kinematics equation:

vf^2 = vi^2 + 2a(delta)x

vf^2 = 0 + 2*(-9.8)*(82)

vf = sqrt(1607.2) = 40.09m/s

The is traveling with a velocity of 40.1m/s when it hits the ground.

Annie has 100 mL of honey. The honey has a mass of 145 g. What is the density of the honey?

Answers

Answer:

The answer is 1.45 g/mL

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question we have

[tex]density = \frac{145}{100} \\ [/tex]

We have the final answer as

1.45 g/mL

Hope this helps you

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