-- The speed of light in air is very close to 3 x 10⁸ m/s.
Whatever the actual number is, it's equivalent to roughly
7 times around the Earth in 1 second. So for this kind of
problem, you can assume that we see things at the same time
that they happen; don't bother worrying about how long it takes
for the light to reach you.
-- For sound, it's a different story. Sound in air only travels at
about 340 m/s. It takes sound almost 5 seconds to go 1 mile.
-- Now, the lightning and thunder happen at the same time.
The light travels to you at the speed of light, so you see the
lightning pretty much when it happens. But the sound of the
thunder comes poking along at 340 m/s, and arrives AFTER
the sight of the lightning.
The length of time between the sight and the sound is about
99.9999% the result of the time it takes the sound to reach you.
If the thunder arrived at you 3 seconds after the light did, then
the sound traveled
(340 m/s) x (3 s) = 1,020 meters .
(about 0.63 of a mile)
(If you're worried about ignoring the time it takes
for the light to reach you ...
It takes light 0.0000034 second to cover the same 1,020 meters,
so including it in the calculation would not change the answer.)
the answer is A.
because it says THE AIR which means there is air in the balloon
Answer:
a. one-fourth its original value.
Explanation:
Sound is threated as a spherical wave. The intensity of the sound is inversely proportional to the area of the wavefront (). Therefore, it is inversely proportional to the square of the distance (r) to the sound source. So, if you double your distance, the intensity of the sound reduces to one-fourth its original value.
Answer:
After 11.62 sec car will axceed the speed limit
Explanation:
We have given constant acceleration
As the car starts from rest so its initial velocity u = 0 m/sec
Final velocity v = 65 miles/hr
We know that 1 mile = 1609 meters
And 1 hour = 3600 sec
So
From first equation of motion v = u+at
So
t = 11.62 sec
So after 11.62 sec car will axceed the speed limit