Physics

posted by .

You are standing at the foot of the Bank of America building in San Francisco, which is 52 floors (237 m) high. You launch a ball straight up in the air from the edge of the foot of the building. The initial vertical speed is 70 m/s.
a. How high up does the ball go?
b. How fast is the ball going right before it hits the top of the building?
c. For how many seconds total is the ball in the air?
(Not sure which equation to use, that's the main reason why I'm asking the question. I don't want to use the wrong equation.)

  • Physics -

    a. Use conservation of energy. The ball rises to a maximum height H such that
    gH = Vo^2/2
    H = (1/g)*(1/2)*Vo^2 = 250 m

    Vo is the initial velocity that it is thrown.

    b. At the top of the building, where Y = 237 m,
    Vo^2/2 = V^2/2 + g*Y
    Solve for V
    V^2/2 = (1/2)(4900)-(g*237)
    = 2450 - 2323 = 127 m^2/s^2
    V = 15.9 m/s

    c. It takes Vo/g = 7.14 s to go up and the same time to come down.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A ball is thrown at an angle of 37.1degrees above the horizontal from a point on the top of a building and 60m from the edge of the building. It just misses the edge of the building and continues on towards the ground. The building …
  2. physics, please help me, this question is hard

    John Stands at the edge of a flat roof of a three story building and throws a 180g ball straight up into the air that reaches a height of 3.0 meters above the roof. ( building is 14 meters high) A. What is the initial speed of the …
  3. Physics

    Standing on the top ledge of a 55 m high building you throw a ball straight up with an initial speed of 45 m/s. How long to the nearest second, does it take to hit the ground?
  4. Physics

    Standing on the top ledge of a 55 m high building you throw a ball straight up with an initial speed of 29 m/s. How long to the nearest second, does it take to hit the ground?
  5. Sports

    Does San Francisco have any foot ball or basketball teams?
  6. Physics

    suppose you are standing on the edge of a cliff 400 m high and you throw 2 balls in the air: one (ball a) directly upward with a speed of 17.6 m/s and one (Ball b) directly downward with a speed 17.6 m/s. 1.) how high will ball A rise?
  7. Physics

    suppose you are standing on the edge of a cliff 400 m high and you throw 2 balls in the air: one (ball a) directly upward with a speed of 17.6 m/s and one (Ball b) directly downward with a speed 17.6 m/s. 1.) how high will ball A rise?
  8. Calc

    A ball is thrown straight up from the top of a 200 foot building with an initial velocity of 40feet/second. acceleration due to gravity is -32feet/second. a) find a formula for the height of the ball at time t. b) how high does the …
  9. science

    A boy is standing at the top of the a building, 40 m high. He leans over the side and throws a pebble vertically upwards from the edge of the building at 12m.s^-1. The pebble reaches the ground at the foot of the building. Calculate …
  10. Physics

    a worker on the roof of a building that is under construction dropped a 0.125 kg wrench over the edge. another workman on the 8th floor saw the wrench go by and determined that its speed at that level was 33.1 m/s. the first floor …

More Similar Questions