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3 years ago

Wheat ground into flour is an example of a ___ change?

Physics

1 answer:

EleoNora [17]3 years ago

6 0

Oml... Its physical... Unless if your turning that wheat into bread by using fire it would be chemical.

Yeeeeeeeetus

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A 20 newton force moves an object southeast. What two properties of force have been described?

Galina-37 [17]

Answer:

The answer is C

Explanation:

Force is a vector quantity so it has both magnitude and direction. The question shows 20N act as magnitude and Southeast act as direction.

7 0

3 years ago

Which of the following statements are true?

aleksley [76]

Good conductors of electricity have larger conductivity values than insulators.

A material that obeys Ohm's law reasonably well is called an ohmic conductor or a linear conductor.

The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed.

Answer: Options 1, 2 and 4.

<u>Explanation:</u>

In physics and electrical engineering, a conductor is an article or kind of material that permits the progression of charge in at least one headings. Materials made of metal are basic electrical conduits.

Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them. Most atoms hold on to their electrons tightly and are insulators.

5 0

3 years ago

two astronauts are taking a spacewalk outside the International Space Station the first astronaut has a mass of 64 kg the second

Fittoniya [83]

Answer:

Approximately $0.88\; {\rm m \cdot s^{-1}}$ to the right (assuming that both astronauts were originally stationary.)

Explanation:

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

Since momentum of this system (of the astronauts) conserved:

$\begin{aligned} &(\text{Total Final Momentum}) \\ &= (\text{Total Initial Momentum})\end{aligned}$ .

Assuming that both astronauts were originally stationary. The total initial momentum of the two astronauts would be $0$ since the velocity of both astronauts was $0\!$ .

Therefore:

$\begin{aligned} &(\text{Total Final Momentum}) \\ &= (\text{Total Initial Momentum})\\ &= 0\end{aligned}$ .

The final momentum of the first astronaut ( $m = 64\; {\rm kg}$ , $v = 0.8\; {\rm m\cdot s^{-1}}$ to the left) would be $p_{1} = m\, v = 64\; {\rm kg} \times 0.8\; {\rm m\cdot s^{-1}} = 51.2\; {\rm kg \cdot m \cdot s^{-1}}$ to the left.

Let $p_{2}$ denote the momentum of the astronaut in question. The total final momentum of the two astronauts, combined, would be $(p_{1} + p_{2})$ .

$\begin{aligned} & p_{1} + p_{2} \\ &= (\text{Total Final Momentum}) \\ &= (\text{Total Initial Momentum})\\ &= 0\end{aligned}$ .

Hence, $p_{2} = (-p_{1})$ . In other words, the final momentum of the astronaut in question is the opposite of that of the first astronaut. Since momentum is a vector quantity, the momentum of the two astronauts magnitude ( $51.2\; {\rm kg \cdot m \cdot s^{-1}}$ ) but opposite in direction (to the right versus to the left.)

Rearrange the equation $p = m\, v$ to obtain an expression for velocity in terms of momentum and mass: $v = (p / m)$ .

$\begin{aligned}v &= \frac{p}{m} \\ &= \frac{51.2\; {\rm kg \cdot m \cdot s^{-1}}}{64\; {\rm kg}} && \genfrac{}{}{0}{}{(\text{to the right})}{} \\ &\approx 0.88\; {\rm m\cdot s^{-1}} && (\text{to the right})\end{aligned}$ .

Hence, the velocity of the astronaut in question ( $m = 58.2\; {\rm kg}$ ) would be $0.88\; {\rm m \cdot s^{-1}}$ to the right.

5 0

2 years ago

A child jumps from a moving sled with a speed of 2.2 m/s and in the

butalik [34]

The initial velocity of the sled will be 7.34 m/sec. V is the initial velocity of the sled.

<h3>What is the law of conservation of momentum?</h3>

According to the law of conservation of momentum, the momentum of the body before the collision is always equal to the momentum of the body after the collision.

The given data in the problem is;

(m₁) mass of child = 38 kg

(u₁) is the initial velocity child = 2.2 m/s

(m₂) is the mass of sled = 68 kg

(u₂) is the initial velocity of sled = ?

(v) is the velocity after collision = 5.5 m/s

According to the law of conservation of momentum;

Momentum before collision =Momentum after collision

$\rm m_1u_1 + m_2u_2 = v(m_1 + m_2)\\\\(38 \times 2.2) + (68 \times V) = 5.5 \times (38+68) \\\\ 83.6 + 68V = 5.5 \times 106 \\\\ 83.6 + 68V =583 \\\\ \rm 68\ V= 583 -83.6 \\\\ \rm 68 \ V= 499.4\\\\ V= 7.34 \ m/sec$