Answer:
Part a)

Part b)


Part c)
equation of position in x direction is given as

equation of position in y direction is given as

Part d)

Part e)
H = 88.5 m
Part f)
t = 1.2 s
Explanation:
As we know that ball is projected with speed
v = 8.10 m/s at an angle 18 degree below the horizontal
so we will have




Part a)
Since it took t =4 s to reach the ground
so its initial y coordinate is given as



Part b)
components of the velocity is given as




Part c)
equation of position in x direction is given as

equation of position in y direction is given as

Part d)
distance where it will strike the floor is given as



Part e)
Height from which it is thrown is same as initial y coordinate of the ball
so it is given as
H = 88.5 m
Part f)
time taken by ball to reach 10 m below is given as


t = 1.2 s
Answer: The wave can flip upside down.
Reflection is the bending of a wave when it cannot pass through. For example, plain mirrors which are flat, a ray of light hits the mirror and is reflected from the mirror since it cannot pass through
When reflection occurs the speed and frequency of the wave does not change but the wave is flipped upside down.
The speed does not change because speed is affected by the change in medium the frequency also remains the same since the energy of the wave does not change.