Answer:
Acceleration from gravity is always constant and downward, but the direction and magnitude of velocity change. At the highest point in its trajectory, the ball has zero velocity, and the magnitude of velocity increases again as the ball falls back toward the earth
Explanation:
The shaft is 78m approximately deep. The correct option is D which is 78 meters
<h3>
What are Sound Waves ?</h3>
Sound waves are longitudinal. That is, the direction of the waves is parallel to the direction of its propagation of particles.
Given that a boy finds an abandoned mine shaft in the woods, and wants to know how deep the hole is. He drops in a stone, and counts 4 seconds before he hears the "plunk" of the stone hitting the bottom of the shaft.
- The speed of the sound V = 330m/s
- The time it takes the sound to reach the top = t
Speed V = distance / time
330 = h/t
Make t the subject of formula
t = h/330
As the stone is dropped, initial velocity = 0, Using the formula
h = 1/2gT²
But T = 4 - t
T = 4 approximately
Substitute all the parameters
h = 1/2 × 9.8 × (4)²
h = 4.9 × (16)
h = 78.4m
Therefore, the shaft is 78m approximately deep. The correct option is D which is 78 meters
Learn more about sound wave here: brainly.com/question/16093793
#SPJ1
<span>Objects that fall near Earth’s surface are rarely in free fall.
"Free fall" is the situation where the ONLY force on an object is
the force of gravity, and nothing else.
Objects near Earth's surface are almost always surrounded by air.
If they are falling, then the air is exerting forces on them, and they
are not in "free fall".</span>
Given:
The speed of sound is 340 m/s
Time for the echo is 5.2 s.
Let h = the depth of the canyon.
Because the sound of your voice travels to the bottom of the canyon and back to your ear, the total distance traveled is 2h.
By definition,
distance = velocity * time.
Therefore
2h = (340 m/s)*(5.2 s) = 1768 m
h = 884 m
Answer: The depth is 884 m.
