It takes 6400 years for one gram of radium to decay away to only 1/16 (one-sixteenth) of a gram. The half-life of radium is

Barnard's Star is a red dwarf. It is located 5.9 light years from Earth. (One light year is the same as 9.46 trillion kilometers.) This distance in kilometers is how many trillion kilometers is it?

Two beams of coherent light are shining on the same sheet of white paper. when referring to the crests and troughs of such waves, where will darkness appear on the paper?

A hollow sphere of radius 0.15 m, with rotational inertia I 0.040 kg m2 about a line through its center of mass, rolls without slipping up a surface inclined at 30 to the horizontal.

Do you think the buoyant force would be greater or smaller if the gold cube were suspended in water? Explain your answer.

Two bar magnets are labeled A and B. The ends of each magnet are numbered 1 or 2, but the poles are not labeled. When A1 is brought near B1, the bars repel. Which conclusion is best supported by the data? A.

Protons and neutrons strongly attract when they

How far is Jupiter from the sun?

Steam moves into a cylinder of a steam engine at a constant pressure and does 2.34 J of work on a piston. The diameter of the piston is 3.4 cm and the piston travels 4.6cm. What is the pressure of the steam?

Identify each type of simple machine.

A car's speedometer reads 20 m/s after accelerating, from a standing start, for 25s. What was the magnitude of its acceleration?