Nlm

Ans 1 (10root2)
I did Work =Fx S =change in KE
In finding S if s=ut 1/2at^2 ans matching
But if i do s=ut +1/2at^2 ans diff
How to understand that if accln or deccleration

@siddharthaghosh It's definitely acceleration as there is no intial velocity in y direction and the acceleration is 10/4=2.5 m/s².
The velocity in y direction finally is u+at=0+(2.5)(4)=10m/s.
The velocity intially in xz plane is 10m/s.
This overall velocity is 10√2m/s.

@siddharthaghosh
Take s = ut+ 1/2 at^2 only . If the value of final velocity comes out to be negative that means the the body started moving backward because of the applied force on it.

F=ma
10=4a
a=2.5m/s2
a=(vu)/t
Since the body isn't moving in y axis so we take u as 0
:.v=at=2.5x4=10m/s
Therefore the body is having 2 velocities
10 in xz and 10 in y
And the resultant will be √(10^2+10^2)= 10√2
Therefore no need of using 2nd equation of motion