The driver of a car travelling at 72 kmph observes the light 300 m ahead of him turning red. The traffic light is timed to remain red for 20 s before it turns green . If the motorist wisher to pass the light without stopping to wait for it t turn green , determine .
The speed with which the motorist crosses the traffic light .

Explanation

Given u = 72 kmph `= 72 xx (5)/(18) ms^(-1)`
`= 20 ms^(-1) , s = 300 m, t = 20s, a = ?, v = ?`
`v = u + at = 20 - 0 . 5 xx 20`
`= 10 ms^(-1)`