Question

When cars are coupled, they should be brought together from a few feet apart at a speed of about 1.5 feet per second. This speed is MOST NEARLY equal to ______ MPH.

1) 1.0
2) 1.5
3) 2.0
4) 2.5

Answer 1

The speed of coupling two cars is approximately 0.0045 mph.

Step-by-step explanation:

The speed of coupling two cars is given by the equation:

v = √(2 * a * d)

where v is the final speed, a is the acceleration, and d is the distance. From the given information, the distance is 3.0 m and the acceleration is 2.2 × 10-8 m/s². Plugging these values into the equation:

v = √(2 * 2.2 × 10-8 * 3.0)

v ≈ 0.002 m/s

Converting this speed into miles per hour, we can use the conversion factor from meters per second to miles per hour:

1 m/s ≈ 2.237 mph

Therefore, the speed of coupling two cars is approximately 0.002 m/s * 2.237 ≈ 0.0045 mph. Since none of the given options match this value, the closest option is 1.0 mph (Option 1).