Why do objects accelerate when dropped on Earth?

A system had 150 kj of work done on it and its internal energy increased by 60 kj. How much energy did the system gain or lose a

mina [271]

Answer:

The system loses 90 kJ of heat

Explanation:

We can answer the question by using the 1st law of thermodynamics, which states that:

$\Delta U=Q-W$

where

$\Delta U$ is the change in internal energy of the system

$Q$ is the heat absorbed by the system (positive if absorbed, negative if released by the system)

$W$ is the work done by the system (positive if done by the system, negative if done by the surrounding on the system)

In this problem, we have:

$W=-150 kJ$ is the work done (negative, because it is done by the surrounding on the system)

$\Delta U=+60 kJ$ is the increase in internal energy

Using the equation above, we can find Q, the heat absorbed/released by the system:

$Q=\Delta U+W=+60 kJ+(-150 kJ)=-90 kJ$

And the negative sign means that the system has lost this heat.

8 0

3 years ago

A 7 kg sled is initially at rest on a horizontal road. the sled is pulled a distance of 2.9 m by a force of 42 n applied to the

Artemon [7]

I have no idea on this question.

6 0

3 years ago

A wave of wavelength 0.3 m travels 900 m in 3.0 s. Calculate its frequency.

zzz [600]

Answer:

1000 Hz

Explanation:

The frequency would be 1000 Hz.

The frequency, wavelength, and speed of a wave are related by the equation:

v = fλ ..................(1)

where v = speed of the wave, f = frequency of the wave, and λ = wavelength of the wave.

Making f the subject of the formula:

f = v/λ.........................(2)

Also, speed (v) = distance/time.

From the question, distance = 900 m, time = 3.0 s

Hence, v = 900/3.0 = 300 m/s

Substitute v = 300 and λ = 0.3 into equation (2):

f = 300/0.3 = 1000 Hz

6 0

3 years ago

Modern nuclear bomb tests have created an extra high level of14C in our atmosphere. When future archaeologistsdate samples from

Ipatiy [6.2K]

Answer:

Too old(Ex. if real time is 1000 then they estimate >1000)

Explanation:

This is because with time our planet may have a definite function which describes temperature.(Because of all the factors and global warming except nuclear bomb testing)

Now nuclear test on planet have significant effect on temperature rise.

Also 14°C rise in temperature is good one because of this.

If future archaeologists only consider that uniform function as above mentioned then they estimate more time then the real one.

Thus too old is right answer.

8 0

3 years ago

What do you want to learn about simple machines? (could someone come up with a question about simple machines for me)

bezimeni [28]

Answer:

what are simple machines lol

Explanation:

6 0

2 years ago