1. Quiz_09 Relativity – simultaneity, time dilation, length contraction
Physics 274
9/14/2016

2. A. reaches point A before it reaches point B. Q1
As a high-speed spaceship flies past you at half the speed of light, a strobe light fires at the center of a room aboard the spaceship. As measured by you, the light from the strobe
A. reaches point A before it reaches point B.
B. reaches point B before it reaches point A.
C. reaches points A and B simultaneously.
D. not enough information given to decide
Answer: B (the wavefronts arrive from the bulb arrive at B first with respect to the earth observer).

3. Mavis has a light clock with her on a train.
Q.2
Mavis has a light clock with her on a train.
The train is moving with respect to Stanley.
Observing Mavis’ light clock, Stanley concluded that
it is running
Fast
Slow
At the same rate
B (delta t = gamma delta t_0; time dilation)

4. According to Stanley, Mavis’ clock is running slow.
Q.3
According to Stanley, Mavis’ clock is running slow.
To verify this, Stanley places two of his clocks at two locations, one at the beginning of the light pulse, one at the end of the light pulse. The “proper time” refers to
The time interval of these two events as measured by Mavis’ clock.
The time interval of these two events as measured by Stanley’s two clocks at two locations.
A time interval measured by a clock in the inverted Lorentz frame.
A (proper time, time between events at the same spatial location in one frame)

5. According to Stanley, Mavis’ clock is running slow.
Q.4
According to Stanley, Mavis’ clock is running slow.
Mavis agrees with Stanley that her clock is slow.
Mavis disagrees with Stanley and claims that Stanley’s two clocks at two locations are not synchronized correctly.
Mavis agrees with Stanley that the length of her spaceship is Lorentz contracted.
B (Stanley measures at two different space-time points)