Answer:
dg= 942m
Explanation:
given the depth of the granite Us dg = 500m
time between the explosion t = 0.99s
the speed of sound in granite is Vg = 6000m/s
First of all calculate the time it takes the sound waves to travel down through the lake
Vw = dw/t1
t1 = dw/Vw
t1 = 500/1480
t1 = 0.338s.
Let dg be the depth of the granite basin, so the time it takes for the sound to travel down through the granite is t2 = dg/6000m/s......equation(1)
So the total time it takes to travel down to the oil surface will be
t1/2 = t1 + t2
t1/2= 0.338 + dg/6000.
since the reflection on the oil does not change the speed of sound, the sound will take travelling upto the surface the same time it takes to reach the oil
so; t = 2 t1/2
t1/2 = t/2 = 0.99s/2 = 0.495
Now insert into the values of t1/2 into the equation (1) and solve for dg;
we get 0.495 = 0.338 + dg/6000
dg = (0.495 - 0.338) x 6000
dg = 942m.
Answer:
d(g) = 642m
Explanation:
Given the following data
Depth of the granite d(g) = 500m, the time within the explosion (t) = 0.99secs.
From the fixed parameters, Speed of sound of granite = 1600m/s and speed of sound in water = 1480m/s.
Since it takes 0.99secs time of echo after exploding dynamite at the lake surface at 500m deep lake water, we have to calculate the time it takes for the sound wave to travel down the water
T(w) = d(w)/V(w) = 500/1480
T(w) = 0.388secs
d(g) is the Depth of the granite and we calculate this as
T(2) = d(g)/6000
Therefore, the total time it takes for oil to flow down is given as
To = T(1)+T(2) = 0.388+d(g)/6000....1
Since the reflection of the oil doesn't change speed of the sound, we have that T = 2To
To = t/2 = 0.99/2
To = 0.495secs
Now, we plug in the values into equation 1
0.495 = 0.388+d(g)/6000
0.495-0.388 = d(g)/6000
0.107×6000 = d(g)
d(g) = 642m
