A. If an electron in a hydrogen atom has an energy of - 6.06 * 10^-20 J, which Bohr orbit is it in?

b. If an electron in a hydrogen atom has an energy of - 2.69 * 10^-20 J, which Bohr orbit is it in?

It takes Desmond from 4:00 to 9:00 to swim 27 km. What is his speed?

Suppose that you find the volume of all the oceans to be 1.4*109km3 in a reference book. To find the mass, you can use the density of water, also found in this reference book, but first you must convert the volume to cubic meters.

If a 2 kg ball is at the edge of a 40 meter cliff and falls off, how much kinetic energy will the ball have when it hits the ground?

People in the United States know that water boils at 212F. In Europe, people know that water boils at 100 C. Is the water in the U. S. Different than the water in Europe? What explains the two different temperatures?

If two cars are identical except for the size of their engines, how will that affect their performance on the highway?

Suppose you were to play a trumpet after breathing helium, in which the speed of sound is much greater than in air.

How can we run out of energy if energy cannot be created or destroyed?

When do magnets attract other magnets?

Why do some kinds of ice on Earth change the sea level when they melt while others do not?

Why are carbon and copper classified as elements