An astronomer was looking up at a comet crossing the sky. His data suggested that the comet was traveling about 100,000 mph. If the earth is moving in the opposite direction of the comet, and is moving with a speed of 67,000 mph, what is the speed of the comet relative
to a lonesome alien that is at rest in space?
Select one:
33,000 mph

67,000 mph

167,000 mph

100,000 mph

A( developed during the process of technology design

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?