A bus decreases its speed from 80 kilometers per hour to 60 km per hour in 5 seconds, find the acceleration of the bus.

  • Speed is defined as the rate of change of distance.
  • Acceleration is the rate of change of velocity.

Answer: The acceleration of the bus is -1.112 m/s2

Let us understand the relationship between acceleration, speed and time.

Explanation:

Acceleration a = (V - U) / t

Note that to convert speed unit from km/h to m/sec, we multiply it by 5/18. We need to convert it in terms of seconds as the given time is in seconds.

Given: Initial velocity (U) = 80 km/hr = 80 × 5/18 = 400/18 = 22.22 m/sec

Final velocity (V) = 60 km/hr = 60 × 5/18 = 300/18 = 16.67 m/sec

Acceleration a = (V - U) / t

= (16.67 - 22.22)/5

= -5.55/5

= -1.11 m/s2

Negative sign indicates that the velocity is decreasing.

Therefore, the acceleration of the bus that decreases its speed from 80 kilometers per hour to 60 km per hour in 5 seconds is -1.11 m/s2

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