As you move from left to right across a period the number of valances electrons
a. increases
b. stays the same
c. increase and then decreases
d. decreases

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.

Geologists get to play with chemistry, physics, and history! and what a history you will meet as youwork your way through the course. starting at the beginning, the textbook provides the scientifically acceptedstart of the and promises that you'll get to explore some of the evidence for that scientific view, later inthe semester. meanwhile, which is more nearly correct of the scientifically accepted view? a) the earth formed when the big bang caused older materials to fall together, about 14 billion years ago. b) the earth formed from the falling together of older materials, about 4.6 billion years ago. c) the earth formed in the big bang, about 6000 years ago. d) the earth is eternal, having been here forever and promising to be here forever. e) the earth was assembled by gigantic space beavers, which gnawed down the primordial tree of life andpiled its branches together to form the planet.