1when it comes back to hand : x=0, y=0
plz elaborate bout this fact.....i din get it.....
got this question frm goiit.com but din get its solution....pls temme the approach to such problems
Q-A boy throws a ball upwards with a velocity 20m/s.The wind imparts a horizontal acc. of 4 m/s^2 to the left.The angle @ at which the ball must be thrown so that it returns to his hand is..(g=10)
options
a)tan inv (1.2)
b) tan inv(0.2)
c)tan inv(2)
d)tan inv(0.4)
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UP 0 DOWN 0 0 4
4 Answers
1Let the angle be @
x = 20cos@ t - (0.5)(4)t2
y = 20sin@ t - (0.5)(g)t2
when it comes back to hand : x=0, y=0
t = 40cos@4 = 40sin@g
tan@ = g4 = 2.5
11when it comes back to hand, x and y displacements are zero and so x=0, y=0