Final answer:
The acceleration of a car that changes its speed from 20 m/s to 100 m/s in 20 seconds is 4 m/s², calculated using the formula for acceleration.
Step-by-step explanation:
The question involves calculating the acceleration of a car that changes its speed from 20 m/s to 100 m/s in 20 seconds. Acceleration is defined as the rate at which an object's velocity changes over time. We can use the formula a = (vf - vi) / t, where vf is the final velocity, vi is the initial velocity, and t is the time in seconds to find the acceleration.
Plugging in the values, the acceleration a is equal to (100 m/s - 20 m/s) / 20 s, which simplifies to 80 m/s / 20 s = 4 m/s². Therefore, the correct answer is Option A) 4 m/s².