Why do the Sun, Moon and stars appear to move across the sky?

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Determine the maximum r-value of the polar equation r =3+3 cos 0

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