The drag force experienced by a moving vehicle is directly proportional to the square of its speed. This means that if you increase the speed of the vehicle, the drag force will increase by the square of the speed ratio.
Let's calculate how many times the drag will increase when the speed changes from 55 to 70 mph:
Initial speed (V1) = 55 mph
Final speed (V2) = 70 mph
The ratio of the speeds is:
Speed ratio = (V2 / V1) = (70 mph / 55 mph)
Now, let's calculate the square of the speed ratio:
(Speed ratio)^2 = [(70 mph / 55 mph)]^2 = (1.2727)^2 ≈ 1.618
So, if a vehicle changes its speed from 55 to 70 mph while everything else stays the same, the drag force will increase by approximately 1.618 times, or about 1.618x.