Question

What is the final velocity of a ball rolling down an inclined plane with a velocity of 4.0m/s and accelerate at 2.0m/s² in 5.0s?

Answer 1

By definition, the acceleration is given as follows:

$$a = \dfrac{v_f - v_i}{t}$$

where $v_f, \space v_i = 4.0m/s$ are the final and initial velocities of the ball respectively, and $t = 5.0s$ is the time. Expressing $v_f$ and substituting $a = 2.0m/s^2$, obtain:

$$v_f = v_i + at\\ v_f = 4.0m/s + 2.0m/s^2\cdot 5.0s =14m/s$$

Answer. 14 m/s.