Answer:
10 seconds.
Explanation:
We can use a kinematic equation where we know the final velocity, initial velocity, acceleration, and need to determine the time t:
[tex]\displaystyle v_f = v_i + at[/tex]
The initial velocit is 30 m/s, the final velocity is 0 m/s (as we stopped), and the acceleration is -3 m/s².
Substitute and solve for t:
[tex]\displaystyle \begin{aligned} (0\text{ m/s}) & = (30 \text{ m/s}) + (-3 \text{ m/s$^2$}) t \\ \\ t & = \frac{-30\text{ m/s}}{-3 \text{ m/s$^2$}} \\ \\ & = 10 \text{ s} \end{aligned}[/tex]
Hence, it will take the car 10 seconds to come to a stop.
