The oxidation number of lead (Pb) in the compound PbCl2 has to be

A car engine burns gas at 495 K, and exhausts to the air at 293 K. If it ran at the highest possible efficiency, how much input heat would it take to do 10,000 J of work? (Unit=J)

Ball A is dropped from rest from a window. At the same instant, ball B is thrown downward; and ball C is thrown upward from the same window.

When a bimetallic bar made of copper and iron strips is heated, it

All matter has unique physical properties true or failed

Jack and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jack pushes George's canoe with a force F to separate the two canoes.

Using the atomic symbol above report how many protons, neutron, and electrons an atom of neon contains.

Which of the following is not shorthand to describe one of the three types of ecological relationships? +/+ -/+ +/0 -/0

Which is a characteristic of an electromagnetic wave?

What does the ozone layer absorb? a. Microwaves c. UV radiation b. X-rays d. Infra-red radiation

An object is undergoing shm with period 0.900 s and amplitude 0.320 m. at t = 0 the object is at x = 0.320 m and is instantaneously at rest. calculate the time it takes the object to go (a) from x = 0.320 m to x = 0.160 m and (b) from x = 0.