99 percent of the earth's atmosphere by mass is made up of only elements. These elements are

A) Carbon and oxygen

B) Nitrogen and oxygen

C) Hydrogen and oxygen

D) Helium and hydrogen

Displacement vector of 4 km north, 2 km south, 5 km north, and 5km south combine to a total displacement of? A 2 km South b 16 km south c 16 km north d 2km north?

What is the centripetal acceleration of a small laboratory centrifuge in which the tip of the test tube is moving at 19.0 meters/second in a circle with a radius of 10.0 centimeters?

When the plastic coating around a cord is damaged, why does the cord become hazardous?

Zebras are classified as vertebrates because they have two germ layers. bilateral symmetry. a backbone. a brain.

a man is trying to move a piano by himself, but it will not move, what force must they overcome to start the piano moving?

A penny falls from a windowsill which is 25.0 m above the sidewalk. How much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground?

Show that the Newton has the units of mass times acceleration.

Light travels at 150000000km from the sun to earth in 8 minutes. What speed is this in Km/s

Electricity problem (coulomb's law)

An observer (O) spots a plane (P) taking off from a local airport and flying at a 29° angle horizontal to her line of sight and located directly above a tower (T). The observer also notices a bird (B) circling directly above her.