Question

A car brakes from a speed of 108km/hr to 72km/hr during a displacement of 100m. What is its acceleration

Answer 1

hi friend,


given u=108kmph(5/18)=30m/s

v=72kmph(5/18)=20m/s

s=100m


we know that

v²-u²=2as

by substituting the values

400-900=200a

-500=200a

-2.5m/s²=a



I hope this will help u ;)

Answer 2

Given -
u = 108 km/h  (Initial speed)
   = 108 x 5/18  (Changing in m/s)
   = 30 m/s

v = 72 km/h (Final speed)
   = 72 x 5/18
   = 20 m/s

s = 100 m

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From second equation of motion -
$v^{2}$ = $u^{2}$ + 2as

a = ($v^{2}$ - $u^{2}$)/(2 x s)
a =($20^{2}$ - $30^{2}$)/(2 x 100)
a =(400 - 900)/(2 x 100)
a = -2.5 m/$s^{2}$

Hope it will help u ...

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Best of luck ;)
ROYALJATT