physic--help ---

posted by .

one of the main battery of cannons protecting the entrance to San Francisco Bay were able t horizontally propel 7.3 kg cannon balls with an average speed of 26.2m/s. if the height of the cannon emplacement were 112m above San Francisco Bay,
a. how far from the cannon's muzzle (end of cannon where cannon ball exits) would the cannon ball land?
b. at what would the cannon need to be set so as to land half the distance?
My answer: a. 124m . b. 151 degrees

Are my answers correct??

  • physic--help --- -

    how long does it take to fall 112m?

    4.9t^2 = 112
    t = 4.78 seconds

    horizontal distance traveled is
    4.78s * 26.2m/s = 125.26m

    Rounding could account for the difference in our answers. I assume your 151° fits the equation, but it seems a bit odd to be firing backwards. Look for an acute angle that will give the same answer.

  • physic--help --- -

    Where is 4.9 come from?

  • physic--help --- -

    I got it , thank you !

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    A railway flat car is rushing along a level frictionless track at a speed of 45m/s. Mounted on the car and aimed forward is a cannon that fires 65 kg cannon balls with a muzzle speed of 625m/s. The total mass of the car, the cannon, …
  2. Physical Sciene

    A cannon is fired horizontally from a top of a 15-m platform. What is the cannon balls horizontal speed when it hits the ground 250 m downrange?
  3. physics

    A 500-kg cannon and a supply of 80 cannon balls, each with a mass of 45.0 kg, are inside a sealed railroad car with a mass of 11000 kg and a length of 49 m. The cannon fires to the right; the car recoils to the left. The cannon balls …
  4. physics

    Two identical cannons fire cannonballs horizontally with the same initial velocity. One cannon is located on a platform partway up a tower, and the other is on top, four times higher than the first cannon. How much farther from the …
  5. Physics

    A 500 kg cannon rests on wheels that are free to roll. The cannon fires a 2 kg cannon ball horizontally with an average force of 400 N. What is the acceleration of the cannon ball?
  6. AP Physics

    Momentum One of those Civil War cannons is fired. The Cannon has a mass of 873kg It fires a 35.0kg cannon ball at a velocity of 145 m/s at an elevation angle of 35.0 degrees. The length of the barrel is 2.10m. (a) What is the recoil …
  7. physics

    A spring cannon is fastened to a glider at rest on a horizontal frictionless air track. The combined mass of the cannon and the glider is 0.560kg. The cannon fires a ball with a mass of 50g horizontally at a speed of 14 m/s. How fast …
  8. physics

    A 580 kg cannon and a supply of 41 cannon balls, each with a mass of 38.9 kg, are inside a sealed railroad car with a mass of 31000 kg and a length of 53 m. The cannon fires to the right; the car recoils to the left. The cannon balls …
  9. physics

    A railway flat car is rushing along a level frictionless track at a speed of 45m/s. Mounted on the car and aimed forward is a cannon that fires 65 kg cannon balls with a muzzle speed of 625m/s. The total mass of the car, the cannon, …
  10. physic

    A cannon ball is fired at an angle of 30° above horizontal with an initial speed vi = 55 m/s. Assume the cannon ball leaves the cannon at ground level and ignore air resistance. (a) How long is the cannon ball in the air?

More Similar Questions