Answer:
Apparent depth = 45 cm
Explanation:
The refractive index of water in a pool, n = 4/3
Real depth, d = 60 cm
We need to find its apparent depth when viewed vertically through air. The ratio of real depth to the apparent depth is equal to the refractive index of the material. Let the apparent depth is d'. So,

So, the apparent depth is 45 cm.
Answer:
Upward force on the boy will be 1024 N
Explanation:
We have given mass of the boy m = 80 kg
Acceleration due to gravity 
It is given that elevator is ascending with acceleration of 
So net acceleration on the boy = 9.8+3 = 12.8
( As the car elevator is moving ascending )
So upward force on the boy will be equal to F = m(g+a)
So 
So upward force on the boy will be 1024 N
KE = 2000 J
Explanation:
KE = (1/2)mv^2
= (1/2)(0.100 kg)(200 m/s)^2
= 2000 J