Answer:

Explanation:
To find Depth D of lake we must need to find the time taken to hit the water.So we use equation of simple motion as:
Δx=vit+(1/2)at²

As we have find the time taken now we need to find the final velocity vf from below equation as

So the depth of lake is given by:
first we need to find total time as
t=3.0-1.01 =1.99 s

Answer:
The magnitude of momentum of the airplane is
.
Explanation:
Given that,
Mass of the airplane, m = 3400 kg
Speed of the airplane, v = 450 miles per hour
Since, 1 mile per hour = 0.44704 m/s
v = 201.16 m/s
We need to find the magnitude of momentum of the airplane. It is given by the product of mas and velocity such that,



or

So, the magnitude of momentum of the airplane is
. Hence, this is the required solution.
This happens in basketball. It is known as "jump ball".
<u>Answer:</u> Below 12m of depth, the submarine has to submerge so that it would not be swayed by surface waves
<u>Explanation:</u>
To avoid the surface waves, a submarine has to submerge below the wave base. It is the position below which the motion of the waves is negligible.
This wave base is equal to half of the wavelength. The equation becomes:
Wave base = 
We are given:
Wavelength = 24 m
Putting values in above equation, we get:
Wave base = 
Hence, below 12m of depth, the submarine has to submerge so that it would not be swayed by surface waves