The bus leaves the stop in 5 seconds and increases the speed to 36 km / h, then for 20 seconds the bus travels

The bus leaves the stop in 5 seconds and increases the speed to 36 km / h, then for 20 seconds the bus travels at a constant speed and brakes before the traffic lights. And it moves to a complete stop for 10 seconds. Identify the path?

Let’s write down given:

Initial speed V0 = 0 km / h

t1 = 5 s

V1 = 36 km / h

t2 = 20 s

t3 = 10 s

V2 = 0 km / h

Find :

Path S -?

Let’s translate from the SI system:

V1 = 36: 3.6 = 10 m / s

Let us find the acceleration from zero to 10 m / s a1 = V1 – Vo / t1 × a1 = 10 – 0/5 = 2 m / s.

Find the path in the first five seconds: s1 = at ^ 2/2 s1 = 2 × 5 ^ 2/2 = 25 m

Let’s find the path where it moved with the same speed: S2 = v1 × t2 = 10 m / s × 20s = 200m

Let’s find the acceleration during braking: a2 = v2 – v1 / t3 a2 = 0 – 10/10 = – 1s

Let’s find the last path: S3 = v2 ^ 2 – v1 ^ 2/2 × a2 s3 = 0 – 100/2 × (-1) = 50m

Add up the entire distance covered: s1 + s2 + s3 = s s = 25 + 200 + 50 = 275m

Answer: S = 275 meters