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A bus decreases its speed from 80 km/hr to 60 km/hr in 5s. Find the acceleration of the bus.

By BYJU'S Exam Prep

Updated on: September 25th, 2023

A bus decreases its speed from 80 km/hr to 60 km/hr in 5s, the acceleration of the bus is -1.1 m/s². The rate of change in velocity with respect to time is referred to as acceleration. Due to its magnitude and direction, acceleration is a vector quantity.

Acceleration = Change in velocity/ time

Depending on whether an item is accelerating or decelerating, acceleration can be either positive or negative. In contrast to negative acceleration, which is also known as deceleration or retardation, positive acceleration happens when an object’s velocity rises with time.

Table of content

1. Acceleration of a Bus
2. A bus decreases its speed from 80 km/hr to 60 km/hr in 5s. Find the acceleration of the bus.

Acceleration of a Bus

A change in an object’s velocity is referred to as acceleration. It is possible for an object’s velocity to alter by increasing, decreasing, or changing its direction of motion. A few instances of acceleration include an apple falling to the ground, the moon orbiting the Earth, and a car coming to a stop at a set of traffic lights. Through these illustrations, we can see that acceleration takes place whenever a moving object’s direction changes or its speed rises or falls.

Solution

We must multiply the speed unit by 5/18 in order to convert it from km/h to m/s. The specified time is in seconds, thus we must convert it to seconds.

Initial velocity, u = 80 km/hr = 22.2 m/s

Final velocity, v = 60 km/hr = 16.7 m/s

Time, t = 5s

Let us use the first equation of motion;

v = u + at

Substituting the values;

16.7 = 22.2 + a (5)

So we get;

a = (16.7 – 22.2)/5

a = -1.1 m/s²

A negative value refers to that the bus is decelerating

Therefore, the acceleration of the bus is -1.1 m/s².

Summary