Question

a bus is moving on a straight road with a speed of 126knperhour is brought to rest after after 200m calculate retardation

Answer 1

Answer:

Use v² = u² + 2as ,

where v = 0 , and u = 126km/h * 1000 m/1 km * 1 h/3600 s = 35 m/s

and s = 200 m.

0² = (35 m/s)² + 2(200 m) a

a = -1225 m²/s² / 400 m = -3.063 m/s².

Use v = u + at,

where v= 0, u = 35 m/s ,a = -3.063 m/s²

0 = 35 m/s + (-3.063 m/s²)t ,

t = (-35 m/s) / (-3.063 m/s²) = 11.42 s

Explanation:

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Answer 2

$u = 126 \: kmh {}^{ - 2}$

$u = 35ms {}^{ - 2}$

$v = 0$

$s = 200 \: m$

$\huge\pink{\underline{\mathbb{USING \: FORMULA}}}$

$\huge\purple{v {}^{2} = u {}^{2} + 2as}$

$\large{0 {}^{2} = (35) {}^{2} + 2a \times 200}$

$\large{0 = 1225 + 400 \: a}$

$\large{- 1225 = 400a}$

$\large{a = \frac{ - 1225}{400}}$

$\huge\red{\boxed{\green{a = - 3.06 \: ms {}^{ - 2}}}}$

$Retardation \: is \: 3.06 \: ms {}^{ - 2}$