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3 years ago

What is the answer to this question

Physics

1 answer:

scoundrel [369]3 years ago

7 0

Answer: A

Explanation:

Molecules speed up as heat is added

For example when water is heated as the water gets hotter the molecules speed up causing the water to boil and change phases into a gas (this is called evaporation)

In an ice cube the water molecules are frozen (barely moving compressed tight together) as the ice cube heats up the molecules start speeding up and moving further apart as the ice cube turns into liquid form. So as heat is added molecules speed up, move faster and spread further apart

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A man jogs at a speed of 1.6 m/s. His dog waits 1.8 s and then takes off running at a speed of 3 m/s to catch the man. How far w

inessss [21]

Answer:

The dog catches up with the man 6.1714m later.

Explanation:

The first thing to take into account is the speed formula. It is $v=\frac{d}{t}$ , where v is speed, d is distance and t is time. From this formula, we can get the distance formula by finding d, it is $d=v\cdot t$

Now, the distance equation for the man would be:

$d_{man}=v_{man}\cdot t=1.6\cdot t$

The distance equation for the dog would be obtained by the same way with just a little detail. The dog takes off running 1.8s after the man did. So, in the equation we must subtract 1.8 from t.

$d_{dog}=v_{dog}\cdot (t-1.8)=3\cdot (t-1.8)$

For a better understanding, at t=1.8 the dog must be in d=0. Let's verify:

$d_{dog}=v_{dog}\cdot (1.8-1.8)=3\cdot (0)=0$

Now, for finding how far they have each traveled when the dog catches up with the man we must match the equations of each one.

$d_{man}=d_{dog}$

$1.6\cdot t=3\cdot (t-1.8)$

$1.6\cdot t=3\cdot t-5.4$

$1.4\cdot t=5.4$

$t=\frac{5.4}{1.4}$

$t=3.8571s$

The result obtained previously means that the dog catches up with the man 3.8571s after the man started running.

That value is used in the man's distance equation.

$d_{man}=1.6\cdot t=1.6\cdot (3.8571)$

$d_{man}=6.1714m$

Finally, the dog catches up with the man 6.1714m later.

6 0

3 years ago

An object is dropped from rest from a 70.6 m tower. Air resistance is negligible. After 0.32 seconds, what is magnitude and dire

dem82 [27]

Answer:

1,378.9ms²

Explanation:

Given the following

Distance S = 70.6m

Time t = 0.32secs

Initial velocity = 0m/s

Required

Acceleration

Using the equation of motion

S = ut+1/2at²

Substitute

70.6 = 0+1/2a(0.32)²

70.6 = 0.0512a

a = 70.6/0.0512

a = 1,378.9

Hence the acceleration is 1,378.9ms²

7 0

3 years ago

Một chất điểm chuyển động tròn đều trên một cung tròn bán kính 40 cm. Biết chất điểm đi được 5 vòng trong thời gian là 2 s. Tính

Reika [66]

Nerozumím Tvůj Otázky

Explanation:

Im sorry

5 0

3 years ago

A woman of mass 50 kg is swimming with a velocity of 1.6 m/s. If she stops stroking and glides to a stop in the water, what is t

Snezhnost [94]

Answer:

Impulse of force = -80 Ns

Explanation:

Given the following data;

Mass = 50kg

Initial velocity = 1.6m/s

Since she glides to a stop, her final velocity equals to zero (0).

Now, we would find the change in velocity.

$Change \; in \; velocity = final \; velocity - initial \; velocity$

Substituting into the equation above;

Change in velocity = 0 - 1.6 = 1.6m/s

$Impulse \; of \; force = mass * change \; in \; velocity$

Substituting into the equation, we have;

$Impulse \; of \; force = 50 * -1.6$

Impulse of force = -80 Ns

Therefore, the impulse of the force that stops her is -80 Newton-seconds and it has a negative value because it is working in an opposite direction, thus, bringing her to a stop.

5 0

2 years ago

Which is the one factor that adds to the greenhouse effect? 1. a decrease in the amount of dust in the atmosphere 2. a decrease

lukranit [14]

Answer:

an increase in gasses that absorb heat

Explanation:

Greenhouse effect refers to the gradual increase in the earth's temperature due to an increase in the concentration of certain gases in the atmosphere. These gases are called greenhouse gases and they include; water vapour, nitrogen 1 oxide, carbon IV oxide etc. Green house effect is said to occur when heat radiating outwards from the earth surface towards space is trapped close to the earth's surface due to the presence of greenhouse gases in the atmosphere.

Greenhouse effect leads to increase in the temperature of the earth, melting of polar ice caps and possibly flooding due to a rise in sea levels.

Greenhouse gases act as glass in a greenhouse. They allow heat to pass through onto the earth surface but trap the heat and prevent it from being radiated outwards back to space. Thereby increasing the surface temperature of the earth.

8 0

3 years ago

Read 2 more answers