Question

A car starts from rest and accelerates uniformly at \(3\ \text{m/s}^2\); determine its velocity after \(5\) seconds.

• A. \(10\ \text{m/s}\)
• B. \(15\ \text{m/s}\)
• C. \(20\ \text{m/s}\)
• D. \(25\ \text{m/s}\)

Hint:

For uniformly accelerated motion starting from rest, velocity after time \(t\) simplifies to \[ v = at. \]

Answer 1

The Correct Option is B

Concept: For motion with constant acceleration, we use the kinematic equation \[ v = u + at \] where

• \(u\) = initial velocity
• \(v\) = final velocity
• \(a\) = acceleration
• \(t\) = time

Step 1: {Identify the given quantities.} \[ u = 0 \quad (\text{starts from rest}) \] \[ a = 3\ \text{m/s}^2 \] \[ t = 5\ \text{s} \]
Step 2: {Substitute into the kinematic equation.} \[ v = u + at \] \[ v = 0 + (3)(5) \] \[ v = 15\ \text{m/s} \]
Step 3: {Write the final result.} Thus the velocity of the car after \(5\) seconds is \[ v = 15\ \text{m/s} \]