A car accelerates uniformly from rest to a speed of 20 m/s in 5.0 seconds. What is the acceleration of the car?
Answer and explanation
Correct answer: D. 4.0 m/s^2
- Step 1: Use the first kinematic equation of uniform motion: v = u + a*t.
- Step 2: With initial velocity u = 0, final velocity v = 20 m/s, and t = 5.0 s: a = (v - u) / t = 20 / 5.0 = 4.0 m/s^2.
Answer
4.0 m/s^2.
Why not the others: '5.0 m/s^2' divides 25 by 5; '2.0 m/s^2' computes 20/10; '100 m/s^2' multiplies speed by time instead of dividing.
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