What is the formula for stopping distance at 30 mph?

The correct formula for stopping distance is derived from understanding the basic physics of stopping a vehicle. Generally, for a vehicle moving at a certain speed, the stopping distance can be estimated using the formula:

Stopping Distance = (Speed in mph) x (Reaction Time + Braking Distance)

For a speed of 30 mph, a commonly used approximate calculation for stopping distance is based on the formula where the distance in feet equals the speed times a factor, commonly accepted as 3 for every 10 mph of speed.

In this case, 30 mph would lead to:

Stopping Distance = 30 + (3 x 10) = 30 + 30 = 60 ft when you consider both the reaction time and the braking distance.

However, the choice given showcases a simplified way of estimating stopping distance with the addition of a small constant, where the assumption might miss the complete context of reaction and brake distance.

Thus, given the parameters of the question, the formula indicating that the stopping distance can be approximated as adding a small constant (such as the 3 feet mentioned) to the speed gives a simplified stopping distance formula appropriate for basic calculations, leading to a result of 33 feet at 30 mph.

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