The problem states that a car is moving at a constant speed. Two photos were taken of the car. The time between the photos is 0.5 seconds. The distance between the equally-spaced lines on the road is 1.8 meters. We are asked to find the speed of the car in m/s.

1. Problem Description

The problem states that a car is moving at a constant speed. Two photos were taken of the car. The time between the photos is 0.5 seconds. The distance between the equally-spaced lines on the road is 1.8 meters. We are asked to find the speed of the car in m/s.

2. Solution Steps

First, we need to determine the number of lines the car passed between the two photos. From the first photo, the front of the car is at the first line. From the second photo, the front of the car is at the fourth line. Therefore, the car has passed three lines.

The distance between the lines is 1.8 m. The total distance the car traveled is the number of lines crossed multiplied by the distance between the lines.

$Distance = Number \, of \, Lines \times Distance \, between \, Lines$

$Distance = 3 \times 1.8 \, m = 5.4 \, m$

The time between the two photos is 0.5 seconds.

$Time = 0.5 \, s$

The formula for speed is:

$Speed = \frac{Distance}{Time}$

$Speed = \frac{5.4 \, m}{0.5 \, s} = 10.8 \, m/s$

3. Final Answer

The speed of the car is 10.8 m/s.