---
title: "A driver is traveling at an unknown initial speed when an obstacle is detected. For an unknown reaction time, the car continues at its original constant speed. The driver then brakes with a constant acceleration of \\( -4.0 \\) \\( \\text{m/s}^2 \\) until the car stops.  The total elapsed time is \\( 8.0 \\) \\( \\text{s} \\), and the total distance traveled is \\( 110 \\) \\( \\text{m} \\).  What is the driver’s reaction time?"
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url: "https://nerd-notes.com/ubq/114334/"
date_modified: "2026-08-18T02:37:24+00:00"
---

# A driver is traveling at an unknown initial speed when an obstacle is detected. For an unknown reaction time, the car continues at its original constant speed. The driver then brakes with a constant acceleration of \( -4.0 \) \( \text{m/s}^2 \) until the car stops.

The total elapsed time is \( 8.0 \) \( \text{s} \), and the total distance traveled is \( 110 \) \( \text{m} \).

What is the driver’s reaction time?

A driver is traveling at an unknown initial speed when an obstacle is detected. For an unknown reaction time, the car continues at its original constant speed. The driver then brakes with a constant acceleration of \( -4.0 \) \( \text{m/s}^2 \) until the car stops.

The total elapsed time is \( 8.0 \) \( \text{s} \), and the total distance traveled is \( 110 \) \( \text{m} \).

What is the driver’s reaction time?

- **A.** \( 2.0 \) \( \text{s} \)
- **B.** \( 3.0 \) \( \text{s} \)
- **C.** \( 4.0 \) \( \text{s} \)
- **D.** \( 5.0 \) \( \text{s} \)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/114334/*