Comparing the speed of sound in liquids, gases, and solids, the speed of sound is usually lowest in ( ) and highest in ( ). Solids, liquids

Gases, liquids

Liquids, solids

Gases, solids

Solids, gases

the answer is the 4th one. the speed of sound is lowest in gas and highest in solid and its because the molecules in solid is closer to each other than the molecules in gas and when the molecules are close to each other, they allow the waves of the sound to travel more quickly.

42.11 years old

Explanation:

Given that:

In 2000, a 20-year-old astronaut left Earth to explore the galaxy; her spaceship travels at 2.5 x 10^8 m/s. She returns in 2040

To find her age we use:

Δtm is  time interval for the observer stationary relative to the sequence of

events = 2040 - 2000 = 40 years

Δts is is the time interval for an observer moving with a speed v relative to the  sequence of event

v = velocity = 2.5 x 10^8 m/s

c = speed of light = 3 x 10^8 m/s

Here age in 2000 is 20 year, therefore when she appear she would be 20 year + 22.11 year = 42.11 years old