Q 23

System S' has a velocity u = +0.45c relative to system S,as shown in the figure.The clocks of S and S'are synchronized at t = t' = 0 when the origins O and O' coincide.An event is observed in both systems.The event takes place at x = 600 m and at time t = 1.9 μs,as measured by an observer in S.What is the x'-coordinate of the event,measured by an observer in S'?
A) 380 m
B) 340 m
C) 360 m
D) 350 m
E) 310 m

Q 24

System S' has a velocity u = +0.56c relative to system S,as shown in the figure.The clocks of S and S'are synchronized at t = t' = 0 when the origins O and O' coincide.An event is observed in both systems.The event takes place at x = 800 m and at time t = 3.0 μs as measured by an observer in S.What is the time t' of the event,measured by an observer in S'?
A) 1.8 μs
B) -4.9 μs
C) 1.7 μs
D) 1.3 μs
E) 1.5 μs

Q 25

In an "atom smasher," two particles collide head on at relativistic speeds.If the velocity of the first particle is 0.741c to the left,and the velocity of the second particle is 0.350c to the right (both of these speeds are measured in Earth's rest frame),how fast are the particles moving with respect to each other?
A) 0.866c
B) 1.091c
C) 0.883c
D) 0.788c