Step 1: Understanding the Question:
This is a standard kinematics problem involving uniform acceleration in a straight line.
The phrase "starts from rest" implies an initial velocity of zero. Step 2: Key Formula or Approach:
Use the first equation of motion:
\[ v = u + at \]
Where:
\(v\) = final velocity,
\(u\) = initial velocity,
\(a\) = acceleration,
\(t\) = time. Step 3: Detailed Explanation:
Identify the given parameters:
Initial velocity \(u = 0\) (starts from rest).
Acceleration \(a = 3\ \text{m/s}^2\).
Time \(t = 5\ \text{s}\).
Substitute values into the formula:
\[ v = 0 + (3 \times 5) \]
\[ v = 15\ \text{m/s} \] Step 4: Final Answer:
The velocity of the car after 5 seconds is \(15\ \text{m/s}\).