The apparent backward movement of a planet is called

A. retrograde motion.

B. Kepler's first law of motion.

C. heliocentric motion.

D. eccentricity.

A Norfolk pine is 18 inches tall and grows at a rate of 1.5 feet per year

A 10.0 kilogram mass of iron on earth exerts a downward force of 98 Newtons. On the moon this same 10.0 kilograms of iron is weighed and found to exert a downward force of 16.3 Newtons. How is this possible?

Sound cannot travel through a vacuum. Explain why.

The mass of an electron is 9.11 * * 10 -31 -31 kg. 1) How far apart would two electrons have to be in order for the electric force exerted by each on the other to be equal to the weight of an electron?

How fast is a wave moving if it has a frequency of 35 Hz and there are 6 meters between crests?

What can change scientific knowledge?

6. What is ductility?

During practice, a baseball player hits a very high fly ball, and then runs in a straight line and catches it. Which had the greatest displacement during the time period from the hitting of the ball to its catching

Why are glass fibers stronger than bulk glass?

1. A 2000kg truck at rest accelerates to 45m/s in 7 seconds. What is its change in kinetic energy?