Question

bus decreases its speed from 80 km h–1 to 60 km h–1 in 5 s. Find the acceleration of the bus.

Answer 1

Initial speed   u=80 km/h=80×  

18

5

​  

=22.22 m/s

Final speed    v=60 km/h=60×  

18

5

​  

=16.67 m/s

Using   v=u+at

Or   16.67=22.22+α×5

⟹ a=−1.1 m/s  

2

Answer 2

Answer:

-1.112m/s^2

Explanation:

Given :

Initial velocity of the bus,u => 80km/h  = 80*1000/60*60

=> 22.22m/s

Final velocity occurs the bus,v => 60km/h  = 60*1000/60*60

=> 16.66m/s

Time taken,t => 5s

To Find :

Acceleration,a = ?

Solution :

From first equation of motion we get,

$\sf{}v=u+at$

Put their values and solve for “a”

$\sf{}\implies 16.66m/s=22.22m/s+a\times 5s$

$\sf{}\implies 16.66m/s-22.22m/s=a\times 5s$

$\sf{}\implies -5.56=a\times 5s$

$\sf{}\implies -\dfrac{5.56m/s}{5s}=a$

$\sf{}\implies a=-1.112m/s^2$

$\sf{}\therefore a=-1.112m/s^2$

Therefore,acceleration is equal to -1.112 m/s^2