Answer:
u=2.33 m/s
Step-by-step explanation:
Given that
Height ,h= 45 m
Horizontal distance ,x= 7 m
The initial speed in the vertical direction ,v= 0 m/s
The speed in the horizontal direction = u m/s
In the vertical direction :

( take g= 10 m/s²)
t² = 9
t= 3 s
In the horizontal direction :
x = u t
7 = u x 3
u=2.33 m/s
Therefore the minimum push off speed will be 2.33 m/s.