# IB Physics SpaceTime Diagram

/A tutorial sheet of **true-false** questions on the spacetime diagram is given below.

ɣ=1/√(1-v^{2}/c^{2})

- Albert Einstein was not the first person to use a spacetime diagram.
- The path of a particle in the (x,ct) plane on a spacetime diagram is called its world line.
- A rigid rod is at rest in the S frame. At t=0 the spacetime coordinates of the ends of the rod in S are A=(0,0) and B=(L
_{0},0). The worldlines of A and B have the equations x=0 and x=L_{0}respectively. - In question 3 take ɣ = 5/4 and L
_{0}as 2. Using a spacetime diagram the coordinates of A in S' when ct' = 4 are (-2.5,4) and the coordinates of B are (-0.83,4), the length of the rod in S' being 1.7 approximately. - A rigid rod is at rest in the S' frame. At t'=0 the spacetime coordinates of the ends of the rod in S' are P=(0,0) and Q=(L
_{0},0). The worldlines of P and Q have the equations x=0 and x=L_{0}respectively.