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4 years ago

15

in summer, it is cooler in the ground floor than in the top floor of a building. it is because the warm air rises up due to conv

ention. why does warm air rises up?

1 answer:

Ivanshal [37]4 years ago

6 0

Answer:

because heat evaporates water

Explanation:

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Indiana Jones is in a temple searching for artifacts. He finds a gold sphere with a radius of 2 cm sitting on a pressure sensiti

Vlad1618 [11]

Answer:

Volume of Sand = 0.4 m³

Radius of Sand Sphere = 0.46 m

Explanation:

First we need to find the volume of gold sphere:

Vg = (4/3)πr³

where,

Vg = Volume of gold sphere = ?

r = radius of gold sphere = 2 cm = 0.02 m

Therefore,

Vg = (4/3)π(0.2 m)³

Vg = 0.0335 m³

Now, we find mass of the gold:

ρg = mg/Vg

where,

ρg = density of gold = 19300 kg/m³

mg = mass of gold = ?

Vg = Volume of gold sphere = 0.0335 m³

Therefore,

mg = (19300 kg/m³)(0.0335 m³)

mg = 646.75 kg

Now, the volume of sand required for equivalent mass of gold, will be given by:

ρs = mg/Vs

where,

ρs = density of sand = 1602 kg/m³

mg = mass of gold = 646.75 kg

Vs = Volume of sand = ?

Therefore,

1602 kg/m³ = 646.75 kg/Vs

Vs = (646.75 kg)/(1602 kg/m³)

<u>Vs = 0.4 m³</u>

Now, for the radius of sand sphere to give a volume of 0.4 m³, can be determined from the formula:

Vs = (4/3)πr³

0.4 m³ = (4/3)πr³

r³ = 3(0.4 m³)/4π

r³ = 0.095 m³

r = ∛(0.095 m³)

<u>r = 0.46 m</u>

4 0

3 years ago

An atoms valence electrons are those electrons that have the highest energy true or false

bazaltina [42]

Answer:

True

Explanation:

An atom's valance electrons are those electrons that have the highest energy. Atoms tend to be stable and nonreactive if they have the highestvalence electrons. In the periodic table, the number of valence electrons in each element decreases from left to right across each period.

4 0

4 years ago

The clothing department of a store has a large mirror that consists of three flat mirrors, each arranged so that a person standi

sleet_krkn [62]

According to the law of reflection, when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

So in the above situation, if the incident ray makes an angle of 65° with respect to the normal to the mirror's surface, the angle of reflected ray will also be equal to 65 degrees. The attached image will explain this better.

So the answer is,

c. 65 degrees

5 0

3 years ago

Describe the role of observations in scientific endeavor and explain the characteristics of good observations.

koban [17]

Observations are used in order to collect data and record a variety of interesting or useful key points about the subject or specimen in observation. These observations, if made well, can be recorded and used to supplement a hypothesis.

3 0

3 years ago

When a molecule absorbs an infrared photon it contributes to the ________energy of that molecule.

Tpy6a [65]

Answer: INFRARED ENERGY

5 0

4 years ago