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3 years ago

If you have lifted 10 pounds 2 feet, you have done ___ foot-pounds of work.

Physics

1 answer:

nasty-shy [4]3 years ago

8 0

Work = Force x distance
(10 pounds)(2 feet)
Work = 20 foot-pounds of work

hope this helps :)

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When a fixed amount of ideal gas goes through an isobaric expansion A) its internal (thermal) energy does not change.B) the gas

Bingel [31]

<h2>Answer: its temperature must increase.</h2>

Explanation:

In an isobaric process the pressure remains constant, which means the initial pressure and the final pressure will be the same.

In addition, during this thermodynamic process, the volume of the ideal gas expands or contracts in such a way that the variation of pressure $\Delta P$ is neutralized.

Now, according to the First law of Thermodynamics that establishes the conservation of energy:

$\Delta U=\Delta Q-\Delta W$ (1)

Where:

$\Delta U$ is the internal energy

$\Delta Q$ is the heat transferred

$\Delta W$ is the work

Now, for an isobaric process:

$\Delta W=P\Delta V$ (2)

Where:

$P$ is the pressure (<u>always positive</u>)

$\Delta V$ is the volume variation of the gas

<u />

<u>Here we have two possible results:</u>

-If the gas expands (positive $\Delta V$ ), the work is positive.

-If the gas compresses (negative $\Delta V$ ), the work is negative.

In this case we are talking about the first result (work is positive).

Then, according to the above, equation (1) can be written as follows:

$\Delta U=\Delta Q - P\Delta V$ (3)

Clearing $\Delta Q$ :

$\Delta Q=\Delta U+P \Delta V$ (4)

Then, for an ideal gas in an isobaric process, part of the heat ( $Q$ ) added to the system will be used to do work (positive in this case) and the other part <u>will increase the internal energy</u>, hence <u>the temperature will increase as well.</u>

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3 years ago

a 1500 kg car traveling at 15 m/s to the south collides with a 4500 kg truck that is intially at rest at a spotlight. The car an

harkovskaia [24]

Answer:

3.75 m/s south

Explanation:

Momentum before collision = momentum after collision

m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂

Since the car and truck stick together, v₁ = v₂.

m₁ u₁ + m₂ u₂ = (m₁ + m₂) v

Given m₁ = 1500 kg, u₁ = -15 m/s, m₂ = 4500 kg, and u₂ = 0 m/s:

(1500 kg) (-15 m/s) + (4500 kg) (0 m/s) = (1500 kg + 4500 kg) v

-22500 kg m/s = 6000 kg v

v = -3.75 m/s

The final velocity is 3.75 m/s to the south.

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2 years ago

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A train increase its speed steadily from 10m/s to 20m/s in 1minutes A what is the average speed during this time in m/s B how fa

Ipatiy [6.2K]

If it increased its speed steadily at a constant rate, then the average speed for the minute was

(1/2)(10m/s + 20m/s) = 15 m/s .

Rolling at an average speed of 15 m/s for 1 minute (60 seconds), it travels

(15 m/s) (60 sec) = 900 meters

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chubhunter [2.5K]

Answer:

Short answer, because copper wire does not have high resistance.

Explanation:

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