Motion with Uniform Acceleration - Example 1

Example 1:
An object accelerates from stationary with the acceleration of 4 ms^-2. What is the velocity of the object after 7s?

Answer:
It's advisable to list down all the information that we have.

Initial velocity, u = 0 (Because the motion start from stationary)
Acceleration, a = 4 ms^-2
Time taken, t = 7s
Final velocity, v = ?

The displacement, s, is not involved, hence we select the equation \(v = u + at\) to solve the problem. $$\begin{array}{l}v=u+at\\ v=(0)+(4)(7)\\ v=28m{s}^{-1}\end{array}$$

Reference

$$\begin{array}{l}v=u+at\\ s=ut+\frac{1}{2}a{t}^2\\ v^2=u^2+2as\\ s=\frac{1}{2}(u+v)t\end{array}$$