What causes changes in weather?

a.

Air masses move and meet.

b.

Water evaporates.

c.

The air gets more humid.

d.

Clouds form.

How many grams of nitrogen gas are needed to produce 34 g of ammonia

What determines the pitch of a sound wave

0.05 kg bullet is fired to the north from a 4.0 kg rifle that is initially at rest. The bullet leaves the rifle with a momentum of 20 Ns. Determine the total momentum of the bullet-and-rifle before the bullet is fired?

The moon's gravity is about half as strong as Earth's gravity. True False

6) What force should be applied to compress a spring by 0.19 m if its spring constant is k = 140 N/m?

Comparing and contrasting ionic and covalent bonds?

Elevation above sea level is called

The train traveled 500 kilometers north to Odessa in 2 hours. What's the train's speed? What is the velocity?

Are microwaves and radio waves faster or slower than other types of electromagnetic energy?

If you dive under-water, you notice an uncomfortable pressure on your eardrums due to the increased pressure. The human eardrum has an area of about 70 mm2 (7*10-5m2), and it can sustain a force of about 7 N without rupturing.