GED Science TestPhysical ScienceEasy
A car accelerates uniformly from rest to 20 m/s in 5 seconds. What is the average acceleration of the car?
- A0.25 m/s²
- B100 m/s²
- C4 m/s²
- D15 m/s²
Show answer & explanationAnswer & explanation
Correct answer: C. 4 m/s²
Acceleration is the change in velocity divided by the time taken. The car starts from rest (0 m/s) and reaches 20 m/s in 5 seconds. So, acceleration = (20 m/s - 0 m/s) / 5 s = 4 m/s².
Why the other options are wrong
- A. Incorrectly divided time by velocity (5/20).
- B. Incorrectly multiplied velocity by time (20*5).
- D. Incorrectly subtracted time from velocity (20-5).
Acceleration
The rate at which an object's velocity changes over time.
- Formula: Acceleration = (Final Velocity - Initial Velocity) / Time (a = Δv/t).
- Units: m/s².
- Can be positive (speeding up), negative (slowing down), or involve a change in direction.
Memory trick: Acceleration: A Change in Velocity Over Time.