A1.5 kg tether ball is hit so that it circles the pole with an angular speed of 4m/s

Well, you didn't ask a question, and 4 m/s is not an angular speed.
So all I can offer is a couple of observations:

1). The tension in the rope is

      M V² / R  =  (1.5 kg) x (4 m/s)² / R

                     =  (24 kg-m²/s²) / (distance of the ball from the pole).

2).  Tetherball was the only thing I played at camp,
       more than 60 years ago, and I loved it !
       It was a tough game, because we had to skin
       our own T.Rex and use his hide to make the ball
       and his guts for the rope. 

A. to determine if humans can explore mars safely