Question

a bus is travelling at 54 km/h.the driver applies brakes so that it retards uniformly to stop in 5s find it's retardation also find the distance travelled by the bus in this duration​

Answer 1

Given:-

• Initial velocity (u) = 54×5/18 = 15m/s

• Final velocity (v) = 0m/s

• Time taken (t) = 5s

To Find:-

• Retardation ( a) and Distance(s) covered by bus.

Solution:-

Firstly we have to calculate the retardation.As we know that negative acceleration is called retardation.

By using 1st equation of motion

→ v = u+at

substitute the value we get

→ 0 = 15 + a×5

→ -15 = a×5

→ -15/5 = a

→ a = -3m/s²

∴ The retardation of the bus is 3m/s²

Now Calculating distance covered

By using 3rd equation of motion

→ v² = u² +2as

substitute the value we get

→ 0² = 15² + 2×(-3) ×s

→ -225 = -6 ×s

→ s = -225/-6

→ s = 225/6

→ s = 37.5m

∴ The distance covered by the bus is 37.5metre