The position of a projectile launched from the origin at t = 0 is given by r → = 4 0  i ⁡ ^…

The position of a projectile launched from the origin at t = 0 is given by r = 4 i ^ + 5 j ^ m   at t = 2s. If the projectile was launched at an angle θ  from the horizontal, then θ   is (take g = 10 ms-2).
  1. tan - 1 3 2
  2. tan - 1 2 3
  3. tan - 1 7 4
  4. tan - 1 4 5

Solution

From question, Horizontal velocity (initial),
ux=402=20 m/s
Vertical velocity (initial), 50=uyt+12gt2

50= uy×2+12(-10)×4
     50=2uy-20
      uy=702=35 m/s
  tanθ=uyux=3520=74
 θ=tan-174

Asked in: JEE Main 2014 (09 Apr Online)

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