Blocks 1 kg, 2 kg and 3 kg are connected by a string and spring as shown and initially in equilibrium. Just after the upper string is cut, which statements are correct?

Select all that apply

• Option A

  The 1 kg and 2 kg blocks accelerate downward at 20 m s⁻².

• Option B

  The tension between 1 kg and 2 kg blocks is 10 N.

• Option C

  The 3 kg block has zero initial acceleration.

• Option D

  The spring force changes instantaneously to zero.