Considering that the acceleration is uniform

we apply the equation

with zero initial speed

and we obtain the speed

Thus
The risk when a PWC (Personal Water Craft) passes too closely behind another boat is creating a blind spot. Blind spot can create a collision.
The boat will block the view of the PWC of oncoming boats, as well as the oncoming boat's view of the PWC.So, that's why it is very important to maintain a proper lookout while turning the PWC and beware of your blind spots.
To solve this problem it is necessary to apply the concepts related to Newton's second law and the kinematic equations of movement description.
Newton's second law is defined as

Where,
m = mass
a = acceleration
From this equation we can figure the acceleration out, then



From the cinematic equations of motion we know that

Where,
Final velocity
Initial velocity
a = acceleration
x = displacement
There is not Final velocity and the acceleration is equal to the gravity, then





From the equation of motion where acceleration is equal to the velocity in function of time we have




Therefore the time required is 0.0705s
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
The height of the diving board is given as

now the speed of the diver is given as

when the diver will jump into the water then his displacement in vertical direction is same as that of height of diving board
So we will have



Part b)

plug in the values in the above equation


Part c)
Horizontal distance moved by the diver is given as



so the distance from the edge of the pool is given as


<span>A = area of styrofoam
M = mass of stryofoam = A*h*rho_s
m = mass of swimmer
Total mass = m + M = m + A*h*rho_s
Downward force = g*(total mass) = g*[m + A*h*rho_s]
The slab is completely submerged.
Buoyant force = g*(mass of water displaced) = g*[A*h*rho_w]
Equate these
g*[m + A*h*rho_s] = g*[A*h*rho_w]
m + A*h*rho_s = A*h*rho_w
A*h*[rho_w - rho_s] = m
A = m/[h*(rho_w - rho_s)]</span>