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3 years ago

Distinguish between physical and chemical changes. Include examples in your explanations.

Physics

1 answer:

hram777 [196]3 years ago

6 0

Answer:

Chemical changes are recognized when a substance changes its properties permanently and it cannot be the same substance as before.

Instead the physical changes implies that if you can return to the same substance through a reverse process.

Explanation:

A chemical change is, by example, a combustion, if a sheet of paper burns, its result is ashes, the ashes cannot go back to being a sheet of paper because its properties changed, heat energy was generated that changed matter permanently.

A physical change, by example, is that of freezing water, the water becomes ice, but this can easily become water again if the temperature is increased, its properties do not change and the chemistry of the substance does not change.

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a cylinder has a radius of 2.1cm and a length of 8.8cm .total charge 6.1 x 10^-7C is distributed uniformly throughout. the volum

7nadin3 [17]

The answer for the following problem is explained below.

Therefore the volume charge density of a substance (ρ) is 0.04 × $10^{-1}$ C.

Explanation:

Given:

radius (r) =2.1 cm = 2.1 × $10^{-2}$ m

height (h) =8.8 cm = 8.8 × $10^{-2}$ m

total charge (q) =6.1× $10^{-7}$ C

To solve:

volume charge density (ρ)

We know;

ρ =q ÷ v

volume of cylinder = π ×r × r × h

volume of cylinder =3.14 × 2.1 × 2.1 × $10^{-4}$ × 8.8 × $10^{-2}$

volume of cylinder (v) = 122.23 × $10^{-6}$

ρ =q ÷ v

ρ = 6.1× $10^{-7}$ ÷ 122.23 × $10^{-6}$

ρ = 0.04 × $10^{-1}$ C

Therefore the volume charge density of a substance (ρ) is 0.04 × $10^{-1}$ C.

3 0

3 years ago

135,000 kilometers = how many miles?

DerKrebs [107]

1 mile = 1.609 km

(135,000 km) x (1 mile / 1.609 km) = 83,885.1 miles

5 0

2 years ago

Which has the most momentum?

boyakko [2]

Answer:

Both objects have the same magnitude of momentum.

Explanation:

If an object of mass $m$ is moving at a velocity of $v$ , the momentum of that object would be $m\, v$ .

The $100\; {\rm g}$ ( $0.1\; {\rm kg}$ ) object is moving at a speed of $1\; {\rm m\cdot s^{-1}}$ . The magnitude of the momentum of this object would be $0.1\; {\rm kg} \times 1\; {\rm m\cdot s^{-1}} = 0.1\; {\rm kg \cdot m \cdot s^{-1}}$ .

Similarly, the momentum of the $1\; {\rm g}$ ( $10^{-3}\; {\rm kg}$ ) object moving at a speed of $100\; {\rm m\cdot s^{-1}}$ would be $10^{-3}\; {\rm kg} \times 100\; {\rm m\cdot s^{-1}} = 0.1\; {\rm kg \cdot m \cdot s^{-1}}$ .

Hence, the magnitude of momentum is the same for the two objects.

7 0

1 year ago

You have family members and the relationship you observed in childhood affects the quality of your current relationships?

Ghella [55]

Answer:

Yes, the relationships you observe in childhood affects the quality of your current relationships.

Explanation:

The saying, "Children see, children do," is evidently true. A child's lifestyle and future relationships are greatly affected by the kind of relationships you allow him to see. Thus, it is very important that parents become role models for their kids.

For example, when your parents handle stress by shouting at each other, then most likely you'd also handle stress the same way in the future. So, it is essential that the role models will show the child how to handle stress positively. The experiences that children have at a young age affects their adult life. It influences them and shapes them into who they will become.

If people at home show positive relationships with each other and also supports a child regarding his education, then the child will most likely set positive relationships with his peers and achieve higher degree standards.

Thus, this explains the answer.

4 0

3 years ago

A rifle bullet with mass 8.00g strikes and embeds itself in a block with mass 0.992kg that rests on a frictionless, horizontal s

mafiozo [28]

Answer:

block velocity v = 0.09186 = 9.18 10⁻² m/s and speed bollet v₀ = 11.5 m / s

Explanation:

We will solve this problem using the concepts of the moment, let's try a system formed by the two bodies, the bullet and the block; In this system all scaffolds during the crash are internal, consequently, the moment is preserved.

Let's write the moment in two moments before the crash and after the crash, let's call the mass of the bullet (m) and the mass of the Block (M)

Before the crash

p₀ = m v₀ + 0

After the crash

$p_{f}$ = (m + M) v

p₀ = $p_{f}$

m v₀ = (m + M) v (1)

Now let's lock after the two bodies are joined, in this case the mechanical energy is conserved, write it in two moments after the crash and when you have the maximum compression of the spring

Initial

Em₀ = K = ½ m v2

Final

E $m_{f}$ = Ke = ½ k x2

Emo = E $m_{f}$

½ m v² = ½ k x²

v² = k/m x²

Let's look for the spring constant (k), with Hook's law

F = -k x

k = -F / x

k = - 0.75 / -0.25

k = 3 N / m

Let's calculate the speed

v = √(k/m) x

v = √ (3/8.00) 0.15

v = 0.09186 = 9.18 10⁻² m/s

This is the spped of the block plus bullet rsystem right after the crash

We substitute calculate in equation (1)

m v₀ = (m + M) v

v₀ = v (m + M) / m

v₀ = 0.09186 (0.008 + 0.992) /0.008

v₀ = 11.5 m / s

6 0

3 years ago