<span> Using conservation of energy
Potential Energy (Before) = Kinetic Energy (After)
mgh = 0.5mv^2
divide both sides by m
gh = 0.5v^2
h = (0.5V^2)/g
h = (0.5*2.2^2)/9.81
h = 0.25m
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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

The frictional force is directly proportional to the force that is perpendicular on the surface.
When the body is placed on a horizontal level with zero inclination, the only force acting on the body is the gravitational force which always pulls the body down. The gravitational force, in this case, is the perpendicular force to the surface. Accordingly, this entire force is used to generate friction
Now as the inclination of the surface increases, the gravitational force is no longer the perpendicular force of the body, its value decreases, which means only a part is used to generate frictional force. Consequently, frictional force decreases.
When the inclination reaches 90 degrees, the gravitational force does not act along the normal and accordingly, no friction force is generated.
A variable is a letter so just be like
13a or something like that