Projectile from Height - NEET Physics Questions
← Back to Kinematics

Projectile from Height

Question 1:

A particle is projected horizontally with a speed of 20/√3 m/s, from some height at t = 0. At what time will its velocity make 60° angle with the initial velocity

1. 1 sec
2. 2 sec
3. 1.5 sec
4. 2.5 sec
View Answer

\[ tan \alpha = \frac{-gt}{u} \]

\[ tan (-60^{\circ })= \frac{-10t}{20/\sqrt{3}} \]

Solving t =2 sec

Question 2:

Two bullets are fired horizontally and simultaneously towards each other from roof tops of two buildings 100 m apart and of same height of 200 m, with the same velocity of 25 m/s. When and where will the two bullets collide? (g = 10 m/s²)

1. They will not collide
2. After 2 s at a height of 180 m
3. After 2 s at a height of 20 m
4. After 4 s at a height of 120 m
View Answer
  • Horizontal motion: Bullets move towards each other with relative velocity
    5050     

    m/s. Time to meet:

    t=10050=2 st = \frac{100}{50} = 2 \text{ s} 

  • Vertical motion: Free fall equation:
    H=200−5t2=200−5(2)2=180 mH = 200 - 5t^2 = 200 - 5(2)^2 = 180 \text{ m} 

Answer: (2) After 2 s at a height of 180 m.