The direct relationship between temperature and volume is known as

Charles' law

Explanation:

Charles' law is one of the Gas Laws. Gas laws were given in 18th century and they refer to the relationship between temperature, pressure and volume of gases. Charles' law, given in 1787 by Jacques Charles, states that the volume and temperature (in Kelvin) of a sample of gas is directly proportional to each other provided it is an ideal gas and the pressure is constant.

Lets say,

Volume = V and temperature = T, then

V∝T

think about the oscillation of the toy shown in the video. when the toy is at the highest point of its motion, its velocity is zero and its acceleration is negative.

the arctic is a region of the planet, north of the arctic circle, and includes the arctic ocean, greenland, baffin island, other smaller northern islands, and the far northern parts of europe, russia (siberia), alaska and canada.