Question

A car starts from rest and accelerates uniformly at 2 m/s$^2$. Find its velocity after 10 sec?

• A. 20 m/s
• B. 25 m/s
• C. 15 m/s
• D. 30 m/s

Hint:

For uniform acceleration, always identify the given variables among $u$, $v$, $a$, $t$, and $s$ first.
Selecting the right kinematic equation makes the calculation extremely straightforward and error-free.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks to calculate the final velocity of a vehicle moving along a straight line under uniform acceleration, starting from rest.

Step 2: Key Formula or Approach:

• Since the acceleration is uniform, we can apply the standard first equation of linear kinematics: \[ v = u + at \] where:
$u$ is the initial velocity,
$a$ is the constant acceleration,
$t$ is the elapsed time,
$v$ is the final velocity.

Step 3: Detailed Explanation:

• Extract the values from the problem statement:
The car starts from "rest", which mathematically means the initial velocity is zero: \[ u = 0 \text{ m/s} \] The uniform acceleration is: \[ a = 2 \text{ m/s}^2 \] The duration of motion is: \[ t = 10 \text{ s} \]
• Substitute the values into the kinematic equation:
\[ v = 0 + (2 \text{ m/s}^2 \times 10 \text{ s}) \] \[ v = 20 \text{ m/s} \]

Step 4: Final Answer:
The velocity of the car after 10 seconds is 20 m/s.