¥Special relativity could only be used to describe
anything involving motion in a straight line with constant velocity.
¥
¥The special theory of relativity could not be applied
to situations involving forces, such as electromagnetic forces or the
force of gravity, since they seldom involve motion in a straight line with
constant velocity.
¥
¥Einstein was able to show that no simple modification
of the special theory of relativity could fix these problems. A new theory was required:
¥
¥The
General Theory of Relativity