A ball is fixed to spring attached to fixed axle at the centre of a rotating wheel. The ball and spring are constrained to move in the groove shown in figure. Two observers one in rotating frame of the ball and one on the ground at rest observe its motion. Platform is rotating with constant angular velocity and spring has attained its stable configuration. Choose the correct statement(s):

• A

  Ground observers sees the ball being pulled radially inward by spring and he attributes it as centripetal force.

• B

  Observer on platform sees the ball being pulled outward by centrigugal force that is being balanced by spring force resulting in constant non zero speed of ball.

• C

  Newton's first law is applicable on ball with respect to observer standing on platform

• D

  Newton's second law is applicable with respect to both the observers.