Q7 / 126 · NTA Abhyas (NEET) 2020 · Physics · Motion In Two Dimensions

A projectile is projected from the ground by making an angle of 60° with the horizontal. After 1 s projectile makes an angle of 30° with the horizontal. The maximum height attained by the projectile is (Take g=10 m s-2)

  • A
    45 2 m
  • Correct answer
    B
    45 4 m
  • C
    43 2 m
  • D
    43 4 m

Solution

tan 30°=v0sin 60°-gtv0cos 60°⇒13=v032-g×tV02

⇒ v 0 2 = 3v 0 2 - gt 3

⇒ v 0 = gt 3 = g 3 .

∴Hmax=v02sin2θ2g=300×3/420=454m

Hence, the correct answer is option: 'B'.

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