Particle moves in a straight line with constant acceleration.The displacements in three consecutive seconds?

Question

particle moves in a straight line with constant acceleration. The displacements in three consecutive seconds are S1 , S2 and S3. Then

1. S1, S2 and S3 are in G.P.

2. S3 = S1 + S2

3. S1, S2 and S3 are in A.P.

4. None of these

Answer 1

Acceleration is constant, so velocity would be in an arithmetic progression, and displacement would be, I think, geometric.  I think. It certainly increases faster than an A.P.