Answer:
Wg is positive and WT negative.
(Letters in options are all wrongly written).
Explanation:
Remember that the work of a force is the internal product between the force and the displacement .
Since the displacement is downwards like the weight, the work done by gravity is positive, while the work done by the tension is negative since it points upwards.
Answer:
An increase in air temperature because of its compression.
Explanation:
The Gay-Lussac's Law states that a gas pressure is directly proportional to its temperature in an enclosed system to constant volume.
<em>where P: is the gas pressure, T: is the gas temperature and k: is a constant.</em>
Therefore, due to Gay-Lussac's Law, when the plunger is pushed down very rapidly, the pressure of the air increase, which leads to its temperature increase. That is why cotton flashes and burns.
I hope it helps you!