Kepler's discoveries regarding the motions of the planets were based on the observations of

Copernicus

Artistarchus

Brahe

Ptolemy

What quantity measures the number of complete cycles an oscillation makes per second?

What characteristic does a good conductor possess? 1. Outer electrons of elements in good conductors are loosely held and are able to migrate readily. 2. Outer electrons of elements in good conductors are held tightly and are able to migrate readily.

The cable of a hoist has a cross-sectional area of 80 mm2. The hoist is used to lift a crate weighing 500 kg. The free length of the cable is 30 m. Assume all deformation is elastic. (a) What is the stress on the cable?

What is the power required to raise a 1.81x10^4 newton elevator 12.0 meters in 22.5 seconds? a) 8.04x10^2 W b) 9.65x10^3 W c) 2.17x10^5W d) 4.89x10^6W

Identify whether the following scenarios involve balanced (B) or unbalanced (U) forces: a) A car stopping at a red light b) A ball rolling down a hill c) An airplane flying at constant speed at the same altitude in one direction d) An airplane

Which is a branch of Earth science? physics ecology chemistry geology

A 6,600 kg train car moving at + 2.0 m/s bumps into and locks together with one of mass 5,400 kg moving at - 3.0 m/s. What is their final velocity? A.) - 1.0 m/s B.) + 2.5 m/s C.) - 0.25 m/s D.) + 0.50 m/s

Why does matter absorb sound energy?

What is the speed of a wave if the wave length is 100 m and the period is 20 s? A. 80 m/s B. 120 m/s C. 2,000 m/s D. 5 m/s

Which best explains why magnets can push on or pull other magnets without touching them? North poles always attract each other, and south poles always force each other away.