According to Einstein, events that are simultaneous in one frame of reference
A) are simultaneous in all frames of reference.
B) are not simultaneous in other frames of reference.
C) may or may not be simultaneous in other frames of reference.
The amount of force needed to sustain motion of a rock in outer space is
A) a force equal to its weight.
B) a force less than its weight if friction is absent.
C) none of these
The center of a long uniform log is raised to shoulder level while the other end is on the
ground. If instead, the end of the log is raised to shoulder level, the work required is
A) half.
B) the same.
C) twice.