Final answer:
The rollercoaster rider's acceleration is calculated using the formula a = (v_f - v_i) / t, resulting in an acceleration of 4.5 m/s².
Step-by-step explanation:
To calculate the acceleration of a rollercoaster rider that changes speed from 2 m/s to 20 m/s in 4 s, you can use the formula for uniform acceleration, which is a = (v_f - v_i) / t, where:
- v_f is the final velocity,
- v_i is the initial velocity, and
- t is the time taken to change the velocity.
Substituting the values:
a = (20 m/s - 2 m/s) / 4 s = 18 m/s² / 4 s =
4.5 m/s²
Therefore, the rollercoaster rider's acceleration is 4.5 m/s².