According to my guesses, he should have swung the pendulam bob and noted its time period. In order to observe the effect of mass, he would have repeated the experiment with varied pendulam bobs. Hope this helped!
Answer: Relative to the bus, you are stationary. Relative to a point on the ground, you are walking forward with velocity equal to the velocity of the bus.
As a person walks toward the back of a bus, they are walking towards a stationary object according to their own perspective. However, from an outside perspective, the bus is moving forward with a constant velocity and so relative to that point in motion, you are actually walking backwards with respect to it. This difference in motion means you would not be able have the same experience as the person on the bus when getting off because when you get off you would stop while they continue going forward. The last sentence could be considered a footnote because it only applies if this was an actual situation rather than just an analogy question in a physics test.
Sound travels 1,480 meters per second, which is about 4.3 times as fast as air. Sound travels much slowly in air. This has to do with the frequency, intensity and amplitude of waves, which are affected differently in water and air.