A. In what frame of reference does special relativity apply? b. In what frames must general relativity be used?
c. Describe what happens to time and length at speeds close to the speed of light.

a. The Special relativity postulate states that the laws of physics apply  in all inertia frames of reference

b. General relativity must be uses a curved space-time

c. Time is dilated for a stationary observer relative to one in motion

Time interval observed on an object in a moving frame of reference is less than the same interval observed on a stationary reference frame

Length is contracted

The length of a rod moving with a velocity relative to an observer will appear contracted by a factor , in the direction of the motion.

Explanation:

a person with a mass of 106kg has a weight of 1060n

f is prop to m1xm2 double m1 double force