It does produce 'sound' ... a compression wave traveling through the air. But your ears don't hear a sound that's vibrating less than 20 or 30 times every second. If you could swing your pendulum that fast, you could hear the sound of its vibrations pushing the air around.
Answer:
A star with 15 solar masses is too big to be a main-sequence star.
The zone that gases always accelerate upward is the Luminous flame zone. The fire plume is the column of hot gases, flames and smoke rising above a fire. Gases accelerate upward toward the always luminous flame zone. The luminous flame height is the distance between the base of a flame and the point at which the plume is luminous half the time and transparent half the time.
210 Pb ---> -ie + 210 B:
84 8.3
Part A. For this part, we use two equations for linear
motion:
<span>y = y0 + v0 t + 0.5 g t^2 --->
1</span>
<span>vf = v0 + g t --->
2</span>
First we solve for t using equation 1: y0 = 0 (initial
point at top), y = 250 m, v0 = 0 (at rest)
250 = 0.5 (9.8) t^2
t = 7.143 s
Now we solve for final velocity vf using equation 2:
vf = g t
vf = 9.8 (7.143)
vf = 70 m/s
Part B. First we solve for the time it takes for the sound
to reach the tourist.
t(sound) = 250 / 335 = 0.746 s
Therefore the total time would be:
t = 0.746 s + 0.300 s
t = 1.05 s
<span>Hence there is enough time for the tourist to get out
before the boulder hits him.</span>
