Hot air balloons rise because the heated air is less dense than cold air, so as the warm rises as the molecules spread out. The cold air is pushed downward, where it is also heated and rises. This movement of  air is called...

The string of a helium balloon slips from your hand, and the balloon rises up into the air. When this happens  the balloon rises continually but slows down due to the effect of viscosity.   the balloon rises until it reaches an altitude where its weight equals that of the same volume of air.   the balloon rises until it reaches an altitude where the air and helium densities are equal.   the balloon rises indefinitely because helium is lighter than air.

What happens to the air inside a hot air balloon when it is heated?

A hot air balloon is rising vertically and is observed from a point on the ground500 metres away from the launching position. If the balloon is rising at 5metres per second when it is at a height of 300 metres, find the angle ofelevation to the observer at this time, and the rate at which this is changing.

Why does air cool as it rises?Group of answer choicesair compresses as it risesair expands as it risesthe humidity of the air decreasesthe humidity of the air increasesair loses its moisture

What happens to the surrounding air when warm air rises?