What layer of the atmosphere returns radio and tv broadcasts back to earth?

What is the upper limit to the mass of a neutron star beyond which neutron degeneracy pressure is unable to withstand the force of gravity and the neutron star is crushed out of existence into a black hole?

An engine converts 95% of its energy to mechanical. What happens to the other 5% of its energy?

The pH of pure water at 25°C is 7.0. The enthalpy change of the autoionization of water is + 55.89 kJ/mol. What is the pH of pure water at 100°C?

What must happen for an object at rest to move or change speed?

Chang wants to build a circuit that will light up the bulb from a flashlight. Which component could Chang leave out and still light up the bulb? the switch the battery the wire the light bulb

If an object has a mass of 20 grams and a volume of 40 cm3, what is its density in g/cm3?

Discuss how systematic and random errors influence the precision and accuracy of an experiment.

Matthew rolls a bowling ball with a speed of 2 meters/second. The ball hits the pins with 1.8 joules of kinetic energy. The mass of the bowling ball is kilograms. NextReset

Many schools require freshmen to live

What do hydroelectric plants use to generate electrical energy?