A car accelerates uniformly from rest to a speed of 20m/s in 5 seconds.
What is the magnitude of its acceleration?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer
4 m/s²
Explanation
The formula for acceleration is:
a = (v - u) / t
Where,
• u = 0 m/s (initial velocity)
• v = 20 m/s (final velocity)
• t = 5 s
Substituting the values:
a = (20 - 0) / 5
a = 20 / 5
a = 4 m/s²
Therefore, the acceleration of the car is 4 m/s².
Key Points
• Acceleration is the rate of change of velocity.
• In uniform acceleration, the acceleration remains constant.
• The car starts from rest, so its initial velocity is zero.
• Reaching a speed of 20 m/s in 5 seconds gives an acceleration of 4 m/s².
Additional Facts
• The SI unit of acceleration is metre per second squared (m/s²).
• Positive acceleration indicates an increase in speed.
• Under uniform acceleration, velocity increases at a constant rate with time.