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3 years ago

Explain how thermal energy (temperature) affects chemical changes.

1 answer:

8 0

If bonds are broken, the energy is released, and if bonds are formed, energy is absorbed. During conversions from chemical energy to thermal energy, the energy stored in the chemical bonds are released and this energy causes surrounding molecules to move faster thus increasing the thermal energy of a substance.

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During a race, a runner runs at a speed of 6 m/s. 2 seconds later, she is running at a speed of 10 m/s. What is the runner’s acc

Lapatulllka [165]

Let's calculate the average acceleration. It is the rate of changing speeds. Hence, we need to calculate the difference of speeds. 10-6=4 m/s. The rate is now $\frac{4m/s}{2s} =2m/s^2$ .
In general, the formula for the mean acceleration between two times 1 and 2 is given by:
$\frac{u_2-u_1}{T}$ where v1 and v2 are the speeds at the respective points and T is the time interval between them.

5 0

3 years ago

The seismic activity density of a region is the ratio of the number of earthquakes during a given time span to the land area aff

Natalija [7]

Answer:

0.0059

Explanation:

According to the question the seismic activity density is given by

$\text{Seismic activity density}=\frac{\text{Number of Earthquakes over a given time span}}{\text{The land area affected}}$

Here,

Number of Earthquakes over a given time span = 424

The land area affected = 71300 mi²

So,

$\text{Seismic activity density}=\frac{424}{71300}\\\Rightarrow \text{Seismic activity density}=0.0059$

The seismic activity density is 0.0059

8 0

3 years ago

Read 2 more answers

You want to produce three 2.00-mm-diametercylindrical wires, each with a resistance of 1.00 Ω at room temperature. One wire is g

Vlada [557]

Answer:

(a) L = 128.75 m

(b) L = 182.56 m

(d) Mass of Gold = 7.68 kg = 7680 gram

(e) Cost of Gold Wire = $ 307040

Explanation:

The resistance of the wire is given as:

R = ρL/A

where,

R = Resistance

ρ = resistivity

L = Length

A = cross-sectional area

(a)

For Gold Wire:

ρ = 2.44 x 10⁻⁸ Ω.m

A = πd²/4 = π(2 x 10⁻³ m)²/4 = 3.14 x 10⁻⁶ m²

R = 1 Ω

Therefore,

1 Ω = (2.44 x 10⁻⁸ Ω.m)L/(3.14 x 10⁻⁶ m²)

L = (1 Ω)(3.14 x 10⁻⁶ m²)/(2.44 x 10⁻⁸ Ω.m)

L = 128.75 m

(b)

For Copper Wire:

ρ = 1.72 x 10⁻⁸ Ω.m

A = πd²/4 = π(2 x 10⁻³ m)²/4 = 3.14 x 10⁻⁶ m²

R = 1 Ω

Therefore,

1 Ω = (1.72 x 10⁻⁸ Ω.m)L/(3.14 x 10⁻⁶ m²)

L = (1 Ω)(3.14 x 10⁻⁶ m²)/(1.72 x 10⁻⁸ Ω.m)

L = 182.56 m

(c)

For Aluminum Wire:

ρ = 2.75 x 10⁻⁸ Ω.m

A = πd²/4 = π(2 x 10⁻³ m)²/4 = 3.14 x 10⁻⁶ m²

R = 1 Ω

Therefore,

1 Ω = (2.75 x 10⁻⁸ Ω.m)L/(3.14 x 10⁻⁶ m²)

L = (1 Ω)(3.14 x 10⁻⁶ m²)/(2.75 x 10⁻⁸ Ω.m)

L = 114.28 m

(d)

Density = Mass/Volume

Mass = (Density)(Volume)

Volume of Gold = AL = (3.14 x 10⁻⁶ m²)(128.75 m) = 4.04 x 10⁻⁴ m³

Therefore,

Mass of Gold = (1.9 x 10⁴ kg/m³)(4.04 x 10⁻⁴ m³)

Mass of Gold = 7.68 kg = 7680 gram

(e)

Cost of Gold Wire = (Unit Price of Gold)(Mass of Gold)

Cost of Gold Wire = ($ 40/gram)(7680 grams)

Cost of Gold Wire = $ 307040

7 0

3 years ago

The center of mass of the system is the point at which the total mass of the system could be concentrated without changing the _

Sveta_85 [38]

The centre of mass of the system is the point at which the total

mass of system could be concentrated without changing the moment

of the system.

Centre of Mass is the point at which the whole mass of the system

is assumed to be concentrated.

The general formula for the COM is:

xₙ = Σmₐxₐ / Σmₐ where, a = 1,2,3.........n

Here the term Σ mₐ xₐ is called the first moment of the system and the

denominator expression is called total mass of the system.

Therefore, from this theory we can say that the moment of the system

remain unchanged while calculating the COM.

Hence, The centre of mass of the system is the point at which the total

mass of system could be concentrated without changing the moment

of the system.

learn more about centre of mass here:

brainly.com/question/3454419

#SPJ4

8 0

1 year ago

A bullet with mass m = 0.1 kg grams hits a ballistic pendulum with length L = 3 meters and mass M = 2 kg and lodges in it. When

Mnenie [13.5K]

Answer:

e) v₁ = 29.7 m / s

Explanation:

Let's propose the solution of the problem, let's start at the moment

Initial

p₀ = m v₁

Final

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

The moment is preserved

p₀ = $p_{f}$

m v₁ = (m + M) v

v = m / (m + M) v₁ (1)

a) energy is conserved

Let's look for kinetic energy

Initial

K₀ = ½ m v₁²

Final

$K_{f}$ = ½ (m + M) v²

Let's replace v

$K_{f}$ = ½ (m + M) [m / (m + M) v₁]²

$K_{f}$ = ½ m² / (m + M) v₁²

Let's look for the relationship of these energies

Ko / $K_{f}$ = ½ m v₁² / (½ m² / (m + M) v₁²)

Ko / $K_{f}$ = (m + M) / m = (1 + M / m)²

The kinetic energy changes therefore it is not conserved in the process, the missing energy is converted into potential heat energy during the crash

b) The impulse is conserved because the system is defined as formed by the two bodies and the externals are of action and reaction, so for the complete system the sum is zero and the moment does not change in value

c) in this case the system is already formed by the two bodies and since there is no rubbing the mechanical energy is conserved, transforming from kinetics to potential

d) when the pendulum oscillates the speed changes from v to zero, so the moment is not conserved, this is because there is an external force acting on the system, the force of gravity

e) For this part let's start at the end of the movement

It is system (bullet + block) moves, energy is conserved

Final. Highest point

$Em_{f}$ = U = (m + M) g h

Initial. Lowest point

Em₀ = K = ½ (m + M) v2

Em₀ = $Em_{f}$

½ (m + M) v² = (m + M) g h

v = √ 2gh

Let's look for the height (h) by trigonometry

Cos 15 = x / L

h = L-x

h = L - L cos 15

h = L (1- cos 15)

We replace

v = √ (2gL (1- cos 15))

Now we use equation (1) of momentum conservation

v = m / (m + M) v1

v₁ = (m + M) / m v

v1 = (0.1 +2.0) /0.1 RA (2 9.8 3 (1- cos 15))

v₁ = 21 √ (2.00)

v₁ = 29.7 m / s

6 0

3 years ago