Answer:
Explanation:
If a perfect vacuum existed in any volume, then no sound would be able to propagate through it, because a sound wave is a pressure wave, and there would be identically zero pressure. Of course, we could get into speculations about “dark energy” or “vacuum energy” supporting pressure waves, but let’s not go there.
Answer:
Explanation:
We shall consider all movement with respect to water assuming that river is at rest or motionless .
speed of canoe = 5 m /s
in five minutes , distance between hat and canoe = 5 x 60 x 5
1500 m
This distance will be covered by man in return journey . In this case his speed is 5 m /s again considering river constant .
So this will be covered at 5 m /s
time taken = 1500 / 5 = 300 s
= 5 minutes .
so it will take 5 minutes to row back to reclaim his hat .
Well the diagram would look like the water cycle I think
The data are recorded incorrectly. All of Lucy's data is correct, she just needs to convert her measurements from centimeters to millimeters.
Speed = distance / time
speed = 100 / 11
speed = 9.09m/s
to get rid of meters and get miles you want to multiply by 1 mile then divide by 1609 meters. to get hours, you times the amount of seconds in an hour (3600) and divide by 1 hour
9.09m/s × 1mile / 1609m × 3600s / 1 hour = 20.3 miles / hour
