Mischka is an amateur astronomer. using her telescope, she looks out past the earth’s atmosphere and observes an object with a long, bright, cloud-like tail behind it. what is mischka observing?

an asteroid
a meteorite
a comet
a meteoroid

a comet

Explanation:  

A comet is composed of rock, ice dust and frozen gases. Comets generally reside in the outskirts of the solar system i.e. Kuiper belt and Oort cloud.

When comets enter the solar system, the frozen gases sublimate and form the atmosphere of the comet. It is known as coma. As the comet nears the Sun, the coma expands as more frozen gases sublimate and extends backwards due to solar wind. A huge tail composed of gases and dust is formed and can be observed through telescope from Earth. This must be observed by Mischka.

heat the gas and measure the pressure

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s