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
@siddhartha-ghosh 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.
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.
Since the body isn't moving in y axis so we take u as 0
Therefore the body is having 2 velocities
10 in x-z and 10 in y
And the resultant will be √(10^2+10^2)= 10√2
Therefore no need of using 2nd equation of motion