You could use:
+ MouseKeyboard: On key Right arrow pressed
-> ball: Add force (ball[Physics].VelocityX+240, ball[Physics].VelocityY-240)
+ MouseKeyboard: On key Left arrow pressed
-> ball: Add force (ball[Physics].VelocityX-240, ball[Physics].VelocityY-240)
1, If your ball is using 'Physics', you need to apply the same behaviour to the floor(and/or walls)...or they wont collide.
2, Also set the floor to 'Imovable' to stop it moving.
3, If your getting too much bounce, just playaround with the values.