Ahorizontal line on a distance-time graph means the object is
a. moving at a constant speed.
b. moving faster.
c. slowing down.
d. at rest.

Suppose that a comet that was seen in 563 a.d. by chinese astronomers was spotted again in year 1951. assume the time between observations is the period of the comet and take its eccentricity as 0.986. what are (a) the semimajor axis of the comet's orbit and (b) its greatest distance from the sun?

Which accurately compares concave and convex lenses?

More solar radiation is absorbed by earth’s surface than by