Ball is projected upwards with speed 20 m/s
now using kinematics

here when ball returns back to same position.
total displacement of ball will be zero.


So ball will return to initial position with same speed in opposite direction.
Answer:
Distance, S = 130m
Explanation:
Given the following data;
Initial velocity = 2m/s
Final velocity = 28m/s
Acceleration = 3m/s²
To find the distance, we would use the third equation of motion.
V² = U² + 2aS
Substituting into the equation, we have;
28² = 2² + 2*3*S
784 = 4 + 6S
6S = 784 - 4
6S = 780
S = 780/6
Distance, S = 130m
Answer:
a). a=0.2 
b). x=10m
c). v=2
Explanation:
Force forward push = 2000N
Resistive force due water=1800N
Net force=2000N-1800N
Fn=200N
m=1000kg
t=10sec
a).

b).

c).

Velocity = displacement / time
v = 400 / 2
v = 200 km/h
In short, Your Answer would be 200 km/h
Hope this helps!