Question

an object start moving from resy with intial velocity is 108km/h and its final velocity is is 36km/h and its displacement is 400m fibd the acceleration​

Answer 1

★$\color{darkblue}\underline{\underline{\sf Given-}}$

• Object moving with initial velocity (u) = 108km/h
• Final velocity (v) = 36km/h
• Displacement (s) = 400m

★$\color{darkblue}\underline{\underline{\sf To \: Find-}}$

• Acceleration (a)

★$\color{darkblue}\underline{\underline{\sf Formula \: Used-}}$

Newton's Third Law of Motion

$\color{violet}\bullet\underline{\boxed{\sf v^2=u^2+2as}}$

★$\color{darkblue}\underline{\underline{\sf Solution-}}$

$\underline{\sf Convert \: km/h \: into \: m/s}$

$\implies{\sf u=108\:km/h}$

$\implies{\sf u=108×\dfrac{5}{18}}$

$\color{orange}\implies{\sf u=30\:m/s }$

$\implies{\sf v = 36\:km/h}$

$\implies{\sf v=36×\dfrac{5}{18} }$

$\color{red}\implies{\sf v=10\:m/s}$

$\large\implies{\sf a=\dfrac{v^2-u^2}{2s}}$

$\implies{\sf a=\dfrac{(10)^2-(30)^2}{2×400}}$

$\implies{\sf a=\dfrac{100-900}{800}}$

$\color{red}\implies{\sf a=-1\:m/s^2 }$

★$\color{darkblue}\underline{\underline{\sf Answer-}}$

Acceleration is $\color{red}{\sf -1\:m/s^2}$

Answer 2

$\mathtt{\huge{ \fbox{Solution :)}}}$

Given ,

Initial velocity (u) = 180 km/hr or 30 m/s

Final velocity (v) = 36 km/hr or 10 m/s

Displacement (s) = 400 m

We know that , the Newton's third equation of motion is given by

$\large \mathtt{ \fbox{ {(v)}^{2} - {(u)}^{2} = 2as}}$

Thus ,

(10)² - (30)² = 2 × a × 400

100 - 900 = 800 × a

-800 = 800 × a

a = -800/800

a = -1 m/s²

Hence , the acceleration is -1 m/s²

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