The solar system formed from the
a. collision of two massive stars.
b. collapse of an interstellar cloud.
c. explosion of an interstellar sun.
d. grouping together of asteroids.

In science and physics what is the standard unit of measure for speed?

An architect plans to use solar energy to heat the next house he designs. what principle of absorption and infrared energy can be applied to the design of the new house? how could she apply to those principals?

Calculate a pendulums frequency of oscillation (in hz) if the pendulum completes one cycle in 0.5s.