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3 years ago

How physical properties are important for identifying unknown substances

Physics

1 answer:

dmitriy555 [2]3 years ago

6 0

Answer:

Every characteristic property is unique to one given substance. Scientists use characteristic properties to identify an unknown substance. Characteristic properties are used because the sample size and the shape of the substance does not matter.

Explanation:

A characteristic property is a chemical or physical property that helps identify and classify substances. The characteristic properties of a substance are always the same whether the sample being observed is large or small. Examples of characteristic properties include freezing/melting point, boiling/condensing point, density, viscosity and solubility.

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Objects through which light can pass are referred to as dash objects

Sergio [31]

Answer:

Those objects are called transparent objects...

Explanation:

If only some light can pass through them ,it is called translucent....

If no light can pass through them ,it is called opaque.

3 0

2 years ago

The half-life of a certain element is 100 days. How many half-lives will it be before only one-eighth of this element remains?

Natalka [10]

Answer:

Explanation:

The half-life is the time it takes for the amount of radioactive isotope to halve. Therefore, we have:

- After 1 half-life, only 1/2 of the element will be left

- After 2 half-lives, only 1/4 of the element will be left

- After 3 half-lives, only 1/8 of the element will be left

So, it will take 3 half-lives for the element to become 1/8 of its original amount.

Mathematically, this can be also verified by using the equation

$\frac{N(t)}{N_0}=(\frac{1}{2})^\frac{t}{\tau_{1/2}}$

where

N(t) is the amount of the element left at time t

N0 is the initial amount of the element

$\tau_{1/2}$ is the half-life

Substituting $t=3\tau_{1/2}$ (3 half-lives), we find

$\frac{N(t)}{N_0}=(\frac{1}{2})^3=\frac{1}{8}$

7 0

3 years ago

Which is the best example of Newton's Second Law of Motion? (1 point) Select one: a. A student has on roller skates and she deci

slava [35]

D, I believe is the correct answer. Hope I answered your question, have a good day.<span />

4 0

3 years ago

I was driving along at 20 m/s , trying to change a CD and not watching where I was going. When I looked up, I found myself 46 m

vampirchik [111]

Answer:

6.46393559312 m/s²

Explanation:

Time taken to cover 56 m

$t=\dfrac{56}{29}\ s$

Distance covered in 0.42 seconds

$0.42\times 20=8.4\ m$

From equation of linear motion

$s=ut+\frac{1}{2}at^2$

$8.4+20(\dfrac{56}{29}-0.42)+\dfrac{1}{2}a(\dfrac{56}{29}-0.42)^2=46\\\Rightarrow a=(46-8.4-20(\dfrac{56}{29}-0.42))\times\dfrac{2}{(\dfrac{56}{29}-0.42)^2}\\\Rightarrow a=6.46393559312\ m/s^2$

The minimum acceleration is 6.46393559312 m/s²

5 0

3 years ago

A 60 kg man jumps down from a 0.8 m table. What is the speed when he

Rom4ik [11]

Answer: Speed = 4 m/s

Explanation:

The parameters given are

Mass M = 60 kg

Height h = 0.8 m

Acceleration due to gravity g= 10 m/s2

Before the man jumps, he will be experiencing potential energy at the top of the table.

P.E = mgh

Substitute all the parameters into the formula

P.E = 60 × 9.8 × 0.8

P.E = 470.4 J

As he jumped from the table and hit the ground, the whole P.E will be converted to kinetic energy according to conservative of energy.

When hitting the ground,

K.E = P.E

Where K.E = 1/2mv^2

Substitute m and 470.4 into the formula

470.4 = 1/2 × 60 × V^2

V^2 = 470.4/30

V^2 = 15.68

V = square root (15.68)

V = 3.959 m/s

Therefore, the speed of the man when hitting the ground is approximately 4 m/s

4 0

2 years ago