Final answer:
To determine the speed of the vehicle before the brakes were applied, we can use the concept of skid marks and the coefficient of friction. Using the formula Speed = sqrt(2 x acceleration x skid distance x coefficient of friction), the calculated speed is approximately 54.06 ft/s. Converting this to mph, the speed is approximately 36.81 mph. None of the provided answer choices match this speed.
Step-by-step explanation:
To determine the speed of the vehicle before the brakes were applied, we can use the concept of skid marks. Skid marks are created when a vehicle's tires slide along the road due to braking. The length of the skid mark is related to the speed of the vehicle.
Let's assume that the coefficient of friction between the tires and the road is known and it is 0.55. The formula to calculate the speed of the vehicle is:
Speed = sqrt(2 × acceleration × skid distance × coefficient of friction)
Given that the skid distance is 84 feet, we can plug in the values and solve for speed:
Speed = sqrt(2 × 32.2 ft/s² × 84 ft × 0.55)
Speed = sqrt(2926.336)
Speed ≈ 54.06 ft/s
Thus, the speed of the vehicle before the brakes were applied is approximately 54.06 ft/s. Converting this to miles per hour (mph), the speed is approximately 36.81 mph. None of the given options match this speed, so none of the provided choices are correct.