The answer would be erin out of all of them thank me later :)
        
             
        
        
        
Answer: part a: 19.62m
part b: 19.62 m/s
part a: 2.83 secs
Explanation:If the air resistance is ignored then the swimmer experience free fall under gravity hence
u=0
a=9.81 m/s2
t=2 secs

s=h

Part b

Part c
now we have h=2*19.62=39.24

 
        
             
        
        
        
Answer: 
Explanation:
Given
mass of ball m=10 kg
It is placed at a height of 150 m
It is dropped from the height and allowed to free fall for 40 m
Velocity acquired by the ball during this fall is given by 
Insert u=0, a=g

Kinetic energy at this instant

 
        
             
        
        
        
Answer:
Explanation:
When two forces acting on a line of action and they are equal in magnitude but opposite it direction, it forms a couple.
Torque is defined as the product of either force and the perpendicular distance between the two forces. 
It is a vector quantity.
The net torque is zero, it means the anticlockwise torque is equal to the clockwise torque. 
It means they balances each other.