Question

Finn drew a diagram to compare Einstein’s two postulates of relativity.

A venn diagram with 2 intersecting circles. The circle on the left is labeled first postulate and the circle on the right is labeled second postulate. There is an X in the first postulate circle, a Z in the second postulate circle and a Y in the intersecting area.

Which labels belong in the areas marked X, Y, and Z?

X: applies to objects moving almost at the speed of light
Y: describes the effect of constant motion in space on time
Z: speed of light is always 3.0 × 108 m/s
X: speed of light is always 3.0 × 108 m/s
Y: applies to objects moving almost at the speed of light
Z: describes the effect of constant motion in space on time
X: speed of light through empty space is the same for all observers
Y: laws of physics are the same for all uniformly moving frames of motion
Z: applies to objects with constant velocity
X: laws of physics are the same for all uniformly moving frames of motion
Y: applies to objects with constant velocity
Z: speed of light through empty space is the same for all observers

Answer 1

X: laws of physics are the same for all uniformly moving frames of motion
Y: applies to objects with constant velocity
Z: speed of light through empty space is the same for all observers

(First postulate = principle of relativity; second postulate = constancy of c; the overlap applies to inertial/constant-velocity frames.)