Question

The area of no return at one intersection was calculated to be 59.0 m. What is the minimum length of time the traffic light should be yellow so a vehicle just entering the area of no return can clear the area while maintaining a speed of 70.0 km/h?

11.9 s

9.10 s

6.07 s

3.03 s

Answer 1

$v = 70\frac{km}{h}$

$s = 59.0m$

$v =70* \frac{1000}{3600}\approx 19.44\frac{m}{s}$

$s =v*t$

$t = \frac{s}{v}= \frac{59}{19.44}\approx 3.03s$

$\text{Answer: }3.03\ s$