Question

A car travelling with a speed of 20km/h comes into rest in 0.5 hour what will the value of its retardation

Answer 1

u=20 km/h
v=0 km/h
t=0.5 hr
$a = \frac{v - u}{t} \\ = \frac{0 - 20}{0.5} \\ = - 40 \: m \: {s}^{ - 2}$
retardation= 40 m/s^2

Answer 2

Answer: Information provided to us:

Initial velocity, u = 20 km/h

Final velocity, v = 0 km/h

Time, t = 0.5 hours

Hence,

Acceleration, a = ( v - u ) / t

a = ( 0 - 20 ) / 0.5

a = - 20 / 0.5

a = - 200 / 5

a = - 40 km/h^2

We know that negative acceleration is retardation so,

Retardation, r = - a

r = - ( - 40 )

Retardation = 40 km / h ^ 2

PLS MARK ME BRAINLIEST

Explanation: