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serg [7]
3 years ago
9

Which item is a pure substance?

Physics
2 answers:
hram777 [196]3 years ago
8 0

Answer:

Solid gold. 10 carat indicates gold purity is not 100%. For 24 karat gold is pure gold.

Explanation:

kvasek [131]3 years ago
3 0

Answer:

solid gold

Explanation:

Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Crystals, in general, are pure substances. Tin, sulfur, and diamond are examples of pure substances that are chemical elements.

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Unit 12 Exam
lapo4ka [179]

Answer:

You increase the acceleration of the car.

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3 years ago
Two neutron stars are separated by a distance of 1.0 x 1012 m. They each have a mass of 1.0 x 1028 kg and a radius of 1.0 x 103
son4ous [18]

To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.

Gravitational potential energy can be defined as

PE = -\frac{GMm}{R}

As M=m, then

PE = -\frac{Gm^2}{R}

Where,

m = Mass

G =Gravitational Universal Constant

R = Distance /Radius

PART A) As half its initial value is u'=2u, then

U = -\frac{2Gm^2}{R}

dU = -\frac{2Gm^2}{R}

dKE = -dU

Therefore replacing we have that,

\frac{1}{2}mv^2 =\frac{Gm^2}{2R}

Re-arrange to find v,

v= \sqrt{\frac{Gm}{R}}

v = \sqrt{\frac{6.67*10^{-11}*1*10^{28}}{1*10^{12}}}

v = 816.7m/s

Therefore the  velocity when the separation has decreased to one-half its initial value is 816m/s

PART B) With a final separation distance of 2r, we have that

2r = 2*10^3m

Therefore

dU = Gm^2(\frac{1}{R}-\frac{1}{2r})

v = \sqrt{Gm(\frac{1}{2r}-\frac{1}{R})}

v = \sqrt{6.67*10^{-11}*10^{28}(\frac{1}{2*10^3}-\frac{1}{10^{12}})}

v = 1.83*10^7m/s

Therefore the velocity when they are about to collide is 1.83*10^7m/s

7 0
3 years ago
If there are 20 Earthworms in a garden that covers 5 square meters, what is the population density of the earthworms?
hodyreva [135]

I think, I do think.. that it is D.

Wouldn't it be simple to divide 5 from 20, that would equal 4.

4 earthworms per square meter.

3 0
3 years ago
Read 2 more answers
All rules to find work in changing force in physics ​
saw5 [17]

Answer:

FORCE - rate of change of momentum, ie its changing velocity [change in velocity is of more concern] NEWTON

WORK - product of force and displacement, ie [velocity may be constant or variable but change in position with certain force is of more concern] JOULES

I hope you understood from this..

7 0
2 years ago
A physicist does 100 joules of work on a simple machine that raise a box of bioks through a heigjt of 0.2metres. if the efficien
11Alexandr11 [23.1K]

Answer:

the work converted to thermal energy is 40 J.

Explanation:

Given;

work done by the physicist,w = 100 J

height through which the book is raised, h = 0.2 m

efficiency of machine = 60% = 0.6

The useful work done by the machine is calculated as;

useful work = 0.6 x 100 = 60 J

The wasted energy = 100 J - 60 J

The wasted energy = 40 J

The wasted energy by the machine is possibly converted to thermal energy by the frictional part of the machine.

Therefore, the work converted to thermal energy is 40 J.

5 0
3 years ago
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