Question

In a car moving at constant acceleration, you travel 230 m between the instants at which the speedometer reads 40 km/h and 70 km/h how many seconds does it take you to travel the 230 m ?

Answer 1

The relationship between the distance covered, initial and final speeds, and time can be expressed through the equation,

First equation,

                    2ad = Vf² - Vi²

Substituting the known values,
                   2(a)(0.230 km) = (70 km/h)² - (40 km/h)²
The value of a from the equation is 7173.92 km/h².

Second equation,
                   d = (Vi)(t) + 0.5at²

Substituting the known values,
                    0.230 km = (40 km/h)(t) + (0.5)(7173.92 km/h²)(t²)

The value of t from the equation is 4.1818 x 10^-3 hours which is also equal to 0.2509 minutes or 15 seconds.

Answer: 15 seconds