What is the main reason that the spectra of all stars are not identical? Explain.

A work crew is using a pulley to lift a small piano up the outside of a building to a second-floor balcony. The piano has mass 180 kg. At a height of 3.0 m, what is the piano's gravitational potential energy with respect to the ground? A. 9.8 J B.

For a ship moving against the current, it takes 9 hours to cover a distance of 113.4 miles. how much does it take this ship to return if the rate of the current is 1.9 mph?

There is a 50 g sample of Ra-229. It has a half-life of 4 minutes. How much will be left after 12 minutes?

The strength of the force depends on which two factors?

Which term refers to sections of earth's crust and part of the upper mantle?

Why is it harder to get something moving than to keep it moving?

An advertisement for a new fish food claims that lab studies show that fish grew three inches in three weeks while eating the food. Travis wondered if the food was worth the extra cost. To evaluate the claim in the advertisement, Travis should

What will happen to an astronaut when the jets produce these four forces

What does it mean when the mark on the ramrod disappears into the barrel of the muzzleloader?

Explain the relationship between speed, velocity and acceleration