After the big bang started the universe 13.78 billion years ago, the universe began to rapidly expand. This rapid expansion caused the universe to cool down into a network of gaseous clouds composed mainly of which element?
O Oxygen
Hydrogen
O Neon
O Carbon

What causes the formation of ocean currents?

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

City b is south of city a, and the 200 mile trip by car takes 4 hours. the cities are 120 miles apart in a straight line. what is the velocity of a trip from city a to city b?