A piece of string is attached to a ball and spun around so the ball is in circular motion, what would happen

if somebody cut the string so that it was no longer attached to the ball?

would the ball continue in a straight motion or in a curved motion?

It would continue doing what it was doing at the moment the string was cut .. travelling at a tangent to the circle .. in a straight line.

The ball only had a curved path because of the centripetal (inward) force provided by the string tension .. cutting the string removes this force.

It would go straight out, like what you see in this picture:
http://www.physics-tutorial.net/graphics…