A commuter travels to work along a road with many traffic signals. After stoppin

Question

A commuter travels to work along a road with many traffic signals. After stopping at one red light the commuter accelerates at 2 m/s2. Just as he passes a speed camera, he notices that the next traffic light has turned red and he must stop, which he does by reversing his acceleration and now decelerating at a constant rate of 2 m/s2; coming to a stop just at the traffic light. The distance between the two traffic lights is 800 m.

How much time does he take to get from the first traffic light to the second and its maximum speed over the time given?

Explanation / Answer

here,

as accelerates and deaccelerates is same so he will travel half of distance between traffic light with acc and other half with deacc

therefore

s = u*t + 0.5*a*t^2
400 = 0 + 0.5 * 2 * t^2

t = sqrt (400)

t = 20 s

total time T = 20 * 2 = 40s

time he take to get from the first traffic light to the second is 40s

part 2 : Maximum Velocity

Vmax = Uo + at

Vmax = 2 * 20 = 40 m/s

maxmium Velcoty attained by car while travelling from one light to other is 40m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.