physics

posted by .

Consider a projectile fired horizontally from a cliff of a given height. With what speed must it be fired so that it makes a 45 degree angle with the ground when it hits

  • physics -

    It hits ground with 45° angle when the vertical velocity, vy, is the same as the horizontal velocity, vx, which equals u (initial velocity) if the projectile is fired horizontally and ignoring air-resistance.

    vx=u

    Let H=given height of cliff
    vy²-0²=2gH
    vy²=2gH
    since vy=u,
    u²=2gH
    u=√(2gH)

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    a) A cannonball is fired horizontally from the top of a cliff. The cannon is at height H = 100 m above ground level, and the ball is fired with initial horizontal speed v_0. Assume acceleration due to gravity to be g = 9.80 m/s^2. …
  2. Physics

    Someone posted the question below, stating that they knew the answer to part A but needed help with part B. Well even with the answer for A, I can't figure it out! Can you take a step back from the question below to show me the steps …
  3. PHYSICS!

    A projectile is fired with an initial speed of 32.5 m/s at an angle of 61.4° above the horizontal. The object hits the ground 7.55 s later. What is the absolute value of the difference in height between the launch point and the point …
  4. PHYSICS!

    A projectile is fired with an initial speed of 32.5 m/s at an angle of 61.4° above the horizontal. The object hits the ground 7.55 s later. What is the absolute value of the difference in height between the launch point and the point …
  5. Physics

    A projectile is fired with an initial speed of 31.0 at an angle of 10.0 above the horizontal. The object hits the ground 7.50 later. a. How much higher or lower is the launch point relative to the point where the projectile hits the …
  6. Physics

    A projectile is fired with an initial speed of 28.0 m/s at an angle of 65 degrees above the horizontal. The object hits the ground 9.5 seconds later. a) How much higher or lower is the launch point relative to the point where the projectile …
  7. physics

    A projectile is fired at an angle of 30ᵒ above the horizontal from the top of the cliff 600 ft high. The initial speed of the projectile is 2000 ft/s. how far will the projectile move horizontally before it hits the level ground …
  8. physics

    48 kg projectile is fired at an angle of 30 degree above the horizontal with an initial speed of 1.34 x10^2m/s fro the top of a cliff 150m above level ground, where the ground is taken to be y=0 what is the inital total mechanical …
  9. physics

    a projectile is fired at an angle of 27 above the horizontal from the top of a cliff 500 ft high. The initial speed of projectile is 1670 ft/s. How far will it move horizontally before hitting the level ground at the base of the cliff?
  10. Physics

    A projectile is fired from a height of h meters at a speed of 55m/s and at an angle of 10 degrees above the horizontal. The projectile hits a target at a horizontal distance of 80m from where it was fired and at a vertical height of …

More Similar Questions