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3 years ago

Which of the following is an SI unit

Physics

2 answers:

Elden [556K]3 years ago

7 0

Answer:

Option (D)

Explanation:

SI unit stands for System International. It is a scientific procedure that helps in describing the immensity and characteristic of a naturally occurring important events. These units are internationally accepted and are very widely used in the scientific world.

There are total <u>7 fundamental SI units</u> and they are-

Kg (kilogram)- to express mass
s (second)- to measure time
K (kelvin)- to measure temperature
A (ampere)- to measure current
Mol (mole)- to express the substance amount
cd (candela)- to express intensity of a luminous substance
m (meter)- To measure distance.

Thus, the correct answer is option (D).

Alla [95]3 years ago

3 0

SI will always be in metric, so the answer is D. Meter.

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Why are astronauts weightless in the Space Station? You may find it helpful to watch the video "Newton's Laws of Motion." Why ar

Zolol [24]

Answer:

B) Because the Space Station is constantly in free-fall around the Earth.

Explanation:

Anything that is falling experiences an upward force on them. For example when a person is going down in a lift they will experience something that is pushing them upwards. This happens due to the fact that the total acceleration the body is feeling is less than the acceleration due to graviity.

The force on a body which is falling is

$F=m(g-a)$

Where,

m = Mass of object

g = acceleration due to gravity

a = acceleration the object is experiencing.

a = g. So, the force becomes zero and the object experiences weightlessness.

Hence, the astronauts in the space station experience weightlessness due to fact that the Space Station is constantly in free-fall around the Earth.

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3 years ago

Car A (mass 1100 kg) is stopped at a traffic light when it is rearended by car B(mass 1400 kg). Both cars then slide with locke

viva [34]

Answer:

Part a)

$v_a = 3.94 m/s$

Part b)

$v_b = 3.35 m/s$

Part C)

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

Explanation:

Part a)

As we know that car A moves by distance 6.1 m after collision under the frictional force

so the deceleration due to friction is given as

$a = -\frac{F_f}{m}$

$a = -\frac{\mu mg}{m}$

$a = - \mu g$

now we will have

$v_f^2 - v_i^2 = 2ad$

$0 - v_i^2 = 2(-\mu g)(6.1)$

$v_a = \sqrt{(2(0.13)(9.81)(6.1)}$

$v_a = 3.94 m/s$

Part b)

Similarly for car B the distance of stop is given as 4.4 m

so we will have

$v_b = \sqrt{2(0.13)(9.81)(4.4)}$

$v_b = 3.35 m/s$

Part C)

By momentum conservation we will have

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1400 v_b = 1100(3.94) + 1400(3.35)$

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

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3 years ago

HEYYYY!! PLEASE HELP!!! Describe three machines that humans have designed and explain how the mechanical advantage is used.!!

satela [25.4K]

Answer:

Three machines that humans have created are the lever, the wheel, and the axle, and also a pulley. even though there's actually more. A lever is A rigid bar that is free to move around a fixed point, such as a screwdriver. The wheel and axle, everyone should know what that is and what it does, it lifts heavy objects, moves people quickly, and moves parts of a complex machine. Pulleys are used to lift things, pulleys can be used singly or with many pulleys working together in order to transport people or things. They can also be used to provide power from one shaft to another. ... Construction pulleys are used in order to lift and place heavy materials.

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2 years ago

NEES HELP!!!!

OLga [1]

Answer:

Doppler Theory

Explanation:

it's a theory regarding the change in wave frequency during the relative motion between a wave source and its observer.

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2 years ago

A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 35.0 min

Lubov Fominskaja [6]

Explanation:

Solution:

Let the time be

t1=35min = 0.58min

t2=10min=0.166min

t3=45min= 0.75min

t4=35min= 0.58min

let the velocities be

v1=100km/h

v2=55km/h

v3=35km/h

a. Determine the average speed for the trip. km/h

first we have to solve for the distance

S=s1+s2+s3

S= v1t1+v2t2+v3t3

S= 100*0.58+55*0.166+35*0.75

S=58+9.13+26.25

S=93.38km

V=S/t1+t2+t3+t4

V=93.38/0.58+0.166+0.75+0.58

V=93.38/2.076

V=44.98km/h

b. the distance is 93.38km

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3 years ago