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Alex Ar [27]
3 years ago
7

22 POINTS!!PLEASE HELP

Physics
1 answer:
Zolol [24]3 years ago
8 0

Method of decreasing friction:By polishing: Friction between two surfaces can be reduced by polishing them. The interlocking and projections are minimized by this method.

Ball-bearing:  As the rolling friction less than the sliding friction consequently in rotating machinery, the shafts are fixed on the ball bearing so that the friction can be reduced considerably. For example-the free wheel of a cycle, the axle of a motorcar, the shafts of the motor dynmo etc. are provided with ball-bearing.

<span><span><span>Lubricants: </span>Friction between two surfaces can be decreased by using lubricants. A lubricant is a substance (a solid or a liquid) which forms a thin layer between the two surfaces in contact. It also fills the depressions present in the surfaces of contact and reduces friction considerably. In light machinery thin oils with low viscosity are used, in heavy and fast moving machinery thick oils and solutes (grease) are used.
</span><span>Streamline<span>: </span>The friction due to air is reduced by making the automobiles streamline.</span></span>

Methods of increasing friction:By making the surface rough friction can be increased. Examples of increasing friction-the tires of a motor car and bicycles are made rough to increase the friction .when a ground or surface become slippery after rain or water splashing it is made rough by spreading sand to increase the friction.

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The speed of light in vacuum is exactly 299,792,458 m/s. A beam of light has a wavelength of 651 nm in vacuum. This light propag
sukhopar [10]

Answer:

v=2.58\times10^8m/s

Explanation:

The index of refraction is equal to the speed of light c in vacuum divided by its speed v in a substance, or n=\frac{c}{v}. For our case we want to use v=\frac{c}{n}, which for our values is equal to:

v=\frac{c}{n}=\frac{299792458m/s}{1.16}=258441774.138m/s

Which we will express with 3 significant figures (since a product or quotient must contain the same number of significant figures as the measurement with the  <em>least</em> number of significant figures):

v=2.58\times10^8m/s

4 0
3 years ago
What are 3 artificial and 2 natural sources of electromagnetic radiation?
KatRina [158]

Answer: its b bro

Explanation:

ajafa'jfbA'FJ

8 0
2 years ago
A cooking pot is sitting in a kitchen for several hours unused. Why does it feel cold when you touch it?
masha68 [24]

Answer:

I would go with 2

Explanation:

But i would also not go with my answer. Lol

8 0
3 years ago
The astronomer who discovered the dwarf planet Eris suggests there might be another object far beyond the Kupier belt. If this P
PolarNik [594]

These objects would be classified as extreme trans Neptunian object (ETNO).

Explanation:

ETNO’s are the objects lying beyond the planet Neptune and orbiting the Sun. They follow a highly eccentric path which is tilted. ETNO has been grouped into three major according to their respective perihelia.  

Within this region (beyond Neptune’s orbit), a hypothetical planet has been discovered. It was discovered following its gravitational effect on the other objects of Kuiper Belt (region beyond the orbit of the Neptune- the last planet of our Solar system)

The Planet is assumed to be around 2 times the Earth’s size and around 10 times heavier than Earth.  

4 0
3 years ago
A train moves from rest to a speed of 25 m/s in 30.0 seconds. What is the acceleration?
fredd [130]

Answer:

a = 0.83\ m/s^2

Explanation:

<u>Uniform Acceleration </u>

When an object changes its velocity at the same rate, the acceleration is constant.

The relation between the initial and final speeds is:

v_f=v_o+a.t

Where:

vf  = Final speed

vo = Initial speed

a   = Constant acceleration

t   = Elapsed time

It's known a train moves from rest (vo=0) to a speed of vf=25 m/s in t=30 seconds. It's required to calculate the acceleration.

Solving for a:

\displaystyle a=\frac{v_f-v_o}{t}

Substituting:

\displaystyle a=\frac{25-0}{30}

\boxed{a = 0.83\ m/s^2}

4 0
2 years ago
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