Answer:
A) The crossbeam is moving relative to the observer on the platform so the height appears contracted.
Explanation:
The observer on the train and the beam are in the same reference frame. That means observer on the train will measure the proper length of the beam not the contracted length . the observer is outside and the plank is in the moving system,it will appear to be moving.
A. A flood would have the most positive effect
Answer:
Average speed = 0.35 m/s
Explanation:
Given the following data;
Distance = 1.3 Km
Time = 62 minutes
To find the average speed in m/s;
First of all, we would convert the quantities to their standard unit (S.I) of measurement;
Conversion:
1.3 kilometres to meters = 1.3 * 1000 = 1300 meters
For time;
1 minute = 60 seconds
62 minutes = X
Cross-multiplying, we have;
X = 62 * 60
X = 3720 seconds
Now, we can calculate the average speed in m/s using the formula;


Average speed = 0.35 m/s