Answers

  • Brainly User
2015-07-23T14:43:08+05:30

s = \frac{1}{2}( u + v ) t

t = \frac{2s}{u+v}


Putting right things at right places, you get t = 0.004 s

0
2015-07-23T18:00:57+05:30
U = 20 m/s
v = 0
s = 4cm = 0.04m

v² - u² = 2as
⇒ 0 - 20² = 2×a×0.04
⇒ -400 = 0.08a
⇒ a = -400/0.08 
⇒ a = -5000 m/s²

v = u + at
⇒ 0 = 20 + (-5000)×t
⇒ -5000t + 20 = 0
⇒ -5000t = -20
⇒ t = 20 / 5000 
⇒ t = 0.004 second
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