Question

the impact was the first commercial electric car to be produced after over 60 years of development. during performance tests in 1994, the car reached a top speed of 55 km/h. suppose the car started at rest and then underwent constant acceleration of 11.5 m/s² until it reached its top speed. how long did it take the impact to reach its top speed?

Explanation:

Step1: Convert top - speed to m/s

First, convert the top - speed from km/h to m/s. We know that $1\ km = 1000\ m$ and $1\ h=3600\ s$. So, $v = 55\ km/h=\frac{55\times1000}{3600}\ m/s\approx15.28\ m/s$.

Step2: Use the kinematic equation

The kinematic equation $v = v_0+at$ is used, where $v_0 = 0\ m/s$ (starts from rest), $v$ is the final velocity, $a$ is the acceleration, and $t$ is the time. Rearranging the equation for $t$ gives $t=\frac{v - v_0}{a}$. Substitute $v = 15.28\ m/s$, $v_0 = 0\ m/s$, and $a = 11.5\ m/s^2$ into the equation. Then $t=\frac{15.28 - 0}{11.5}\ s\approx1.33\ s$.

Answer:

$1.33\ s$