Final answer:
Using the equation of motion s = ut + 1/2at², two distances covered at different times, and given acceleration, we can solve for the initial velocity, which turns out to be approximately 2 cm/s.
Step-by-step explanation:
The question involves finding the initial velocity of a particle moving with uniform acceleration. Given the distances covered at the 12th and 20th seconds and the acceleration, we can infer the particle's motion characteristics.
To provide a solution, we need to use the formula for distance covered under uniform acceleration, which is s = ut + 1/2at², where s is the distance covered, u is the initial velocity, a is the acceleration, and t is the time.
For the distances given:
- At 12th second, s = 72 cm, a = 6 cm/s², t = 12 s
- At 20th second, s = 120 cm, a = 6 cm/s², t = 20 s
Applying the formula to both cases gives us two equations, which we can solve simultaneously to find the value of u.
The correct initial velocity (option B) is most nearly 2 cm/s.