Assertion : A solid sphere is rolling on a rough horizontal surface. Acceleration of contact point is zero. Reason : A solid sphere can roll on the smooth surface.

• A

  If both assertion and reason are true and reason is the correct explanation of assertion.
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion.
• Correct answer
  C

  If assertion is true but reason is false.
• D

  If both assertion and reason are false.

Solution

During rolling motion, there is radial acceleration towards the centre. Hence, the contact point moves vertically upward.
On smooth surface, sphere will slide without rolling.

Hence, the correct answer is option: 'C'.