Final answer:
To find final velocity (Vf) with known acceleration and initial velocity, use the formula Vf = Vi + at. Time (t) must also be known to calculate Vf, and at least three variables are needed in motion problems involving constant acceleration.
Step-by-step explanation:
To find the final velocity (Vf) when acceleration (a) and initial velocity (Vi) are given, we can use the equation Vf = Vi + at, where t stands for time. However, if time is not provided, we cannot use this formula directly since we need three known quantities to solve for the fourth in motion problems involving constant acceleration.
If only Vi and acceleration are given without time, additional information is required to find Vf. In physics problems, it is assumed that you have at least three variables to solve for the fourth unless another equation or method can be derived from given information.