Question

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

Answer 1

Given:-

initial velocity (u) = 80 km/hr

final velocity (v) = 60 km/hr

Time = 5s

To find :-

Acceleration of bus.

Solution :-

First, change the velocity in to its SI unit I.e, m/s by multiplying with$\frac{5}{18}$

Now, u = $\frac{200}{9} m</strong><strong>/</strong><strong>s$

v = $\frac{150}{9} m</strong><strong>/</strong><strong>s$

The formula of acceleration is given by formula :-

$\boxed{\sf{ </strong><strong>a = \frac{v - u}{t} </strong><strong>}}$

by putting the value of given quantity,

$\implies$ $a = \frac{ \frac{150}{9} - \frac{200}{9} }{5}$

$\implies$ $a = \frac{ \frac{150 - 200}{9} }{5}$

$\implies$ $a = \frac{ \frac{ - 50}{9} }{5}$

$\implies$ $a = \frac{ - 50}{45}$

$\implies$ $a = \frac{ - 10}{9} m</strong><strong>/</strong><strong>s$

The negative sign shows that the acceleration is decreased i.e,retardation.

hence, acceleration of bus is $\frac{ - 10}{9}m</strong><strong>/</strong><strong>s$