Question

a bus running at a speed of 18 km per hour stopped in 2.5 seconds by applying brakes calculate the retardation produced

Answer 1

u = 18km/h 18 × 5/18 = 5m/s

t = 2.5s

v = 0

a = ?

a = (v - u) / t

= -5/2.5

=
$- 2ms {}^{ - 2}$

Thanks

Answer 2

hello friend...!!!

the speed of the bus = 18 km / hr 

18 km /  hr = 18 x 1000 / 3600 = 5 m / s { convertion }

now , the time = 2.5 sec 

final velocity =  0 m/s

by using equation of motion 

v = u + at 

0 = 5 + a ( 2.5)

therefore ,

a = -5 / 2.5 m/s² 

therefore , a = - 2 m/s²

thus the retardation produced is -2 m/s²

-------------------------------------------------------------------

hope it helps...!!