Two balls are thrown vertically up from same
point on ground with same speed of 20 m/s at an
interval of 2 s. At what height above ground they
will hit each other?
(1) 20 m
(2) 15 m
(3) 10 m
(4) They will never hit
Answers
Answer:
15 m
Explanation:
Two balls are thrown vertically up from same
point on ground with same speed of 20 m/s at an
interval of 2 s. At what height above ground they
will hit each other?
Velocity of Ball = 20 m/sec
Time to Reach at top Using V = U + at
a = -g = -10
=> 0 = 20 +(-10)t
=> t = 2 sec
=> When 1st ball is at top at that moment 2nd ball is thrown from ground
Distance covered by 1st ball till max height
0² - 20² = 2(-10)S
=> S = 20 m
Let say after t sec of 2nd ball thrown both balls hit each other
Distance covered by 1 st Ball = (1/2)10t² = 5t² ( from Max height)
Distance covered by 2nd Ball = 20*t + (1/2)(-10)t² = 20t - 5t²
Both distance will add up to 20 m ( Max height)
20t - 5t² + 5t² = 20
=> 20t = 20
=> t = 1 sec
Distance from Ground = 20t - 5t² = 20 - 5 = 15 m
Answer:
Explanation:
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