If the current in this circuit is 3 A, what must be the value of R3?

vichka [17]

Answer:

e) True, f) False

Explanation:

e) Let consider a close system, that is, a system with no mass interactions with surroundings. Then, we get the following expression by the First Law of Thermodynamics:

$Q_{net,in} - W_{net, out} = \Delta U$ (1)

Where:

$Q_{net, in}$ - Net input heat, measured in joules.

$W_{net, out}$ - Net output work, measured in joules.

$\Delta U$ - Change in thermal energy, measured in joules.

Please notice that work comprises all kind of work (i.e. mechanical, electric, magnetic), whereas heat comprises all heat interactions including chemical and radioactive phenomena.

If thermal energy is released, then $\Delta U < 0$ , which is caused by three scenarios:

(i) $Q_{net,in} < 0$ , $W_{net, out} < 0$ , $|Q_{net,in}|>|W_{net,out}|$

(ii) $Q_{net, in} > 0$ , $W_{net,out} > 0$ , $|Q_{net,in}|$

(iii) $Q_{net,in}< 0$ , $W_{net, out}>0$

In the case $Q_{net,in} > 0$ , $W_{net, out}$ , the thermal energy of the system is increased. Therefore, thermal energy is released during some energy conversions. Answer: True

f) A liquid solidifies when temperature goes below point of fusion, meaning a realease of heat with no work interactions. That is:

$Q_{net, in} = \Delta U$ , $Q_{net, in} < 0$ (2)

If $Q_{net, in} < 0$ , then $\Delta U < 0$ . Then, if a liquid absorbs heat energy, then thermal energy is increase and the liquid does not solidifies. Answer: False.

7 0

2 years ago

Help can’t find the answer no where

katen-ka-za [31]

i'm stuck on that question also

5 0

3 years ago

16

krek1111 [17]

Explanation:

the table and the wooden block

6 0

3 years ago

Read 2 more answers

When a golf ball is hit, it travels at 41 meters per second. The mass of a golf ball is 0.045kg. Calculate the kinetic energy of

Fittoniya [83]

Answer:

75.645 J

Explanation:

The kinetic energy is related to the mass and velocity by the formula ...

KE = 1/2mv²

For the given mass of 0.045 kg, and velocity of 41 m/s, the kinetic energy is ...

KE = 1/2(0.045 kg)(41 m/s)² = 75.645 J

__

The unit of energy, joule, is a derived unit equal to 1 kg·m²/s².

4 0

2 years ago

Describe an example where materials are prepared as fluids so that they can be moved easily

den301095 [7]

Answer:

In general solids are easier to transport than liquids, but the above metal example is a valid one and the only other one that comes to mind is that of concrete. It is mixed as a liquid and transported as such, but then sprayed or laid down to dry and form a solid surface or filler.

Explanation:

5 0

3 years ago