Question

The octopus above is swimming along when it decelerates at 1.5ms-2 for 0.2s to a final speed of 3ms-1. What is the octopus's initial speed?

Answer 1

$$a = {v - v_0 \over t}$$

$$v_0 = v - at$$

Octopus decelerates, therefore a = -1.5 m/s². In the end:

$$v_0 = 3 - (-1,5)*0.2 = 3 + 0.3 = 3.3 m/s$$

Answer: 3.3 m/s.