Physics

posted by .

A ball is thrown upwards at 15m/s from a window 20 metres above the ground. Find: a)How long the ball the takes to reach the level of the window
b)How much longer it takes to reach the ground?
c)What speed it takes to reach the ground?

  • Physics -

    a. = V = Vo + g*t
    Tr = (V-Vo)/g = (0-15)/-9.8 = 1.53 s. =
    Rise time.
    Tf = Tr = 1.53 s. = Fall time.
    T = Tr + Tf = 1.53 + 1.53 = 3.06 s. =
    Time to return to window level.

    b. H = Vo*t + 0.5g*t^2 = 20 m.
    15*t + 4.9t^2 = 20
    4.9t^2 + 15t - 20 = 0
    Use Quadratic Formula.
    T = 1.0 s. To reach Gnd.

    c. V^2 = Vo^2 + 2g*h.
    V^2 = 15 + 19.6*20 = 392
    V = 19.8 m/s.

  • Physics -

    Correction:
    c. V^2 = (15)^2 + 19.6*20 = 617
    V = 24.8 m/s.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physic

    Hi! Question:A ball is tossed from an upper-story window of a building.The ball is given an initial velocity of 7.80m/s at an angle of 21.0 degrees below the horizontal.It strikes the ground 3.00s later. A.How far horizontally from …
  2. Physics

    A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 7.70 m/s at an angle of 23.0° below the horizontal. It strikes the ground 6.00 s later. (Ignore air resistance.) (a) How far horizontally …
  3. Physics Honors

    A basketball is thrown horizontally from a window that is 22 meters high. If the initial velocity of the ball 18 m/s, find how long the ball takes to reach the ground and how far the ball lands from the building?
  4. Physics urgent pls!

    A ball is tossed from an upper-storey window of a building.The ball is given an initial velocity of 8 m/s at an angle of 20 degrees below the horizontal.it strikes the ground 3s later .(a) How far horizontally from the base of the …
  5. physics

    a ball is thrown straight up with a speed of 8.0 m/s from a third-floor window located 13.0 m above ground. Calculate the maximum height, measured from the ground, of the ball; calculate the ball's velocity when it reaches the ground, …
  6. Physics

    Ball A is thrown upward from the top of a building and takes 12 s to hit the ground. Ball B is thrown downward with the same speed as Ball A and takes 7 s to hit the ground. How long does it take for ball A to reach it peak?
  7. physics

    A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 7.50 m/s at an angle of 18.0° below the horizontal. It strikes the ground 5.00 s later. (a) How far horizontally from the base of …
  8. Maths

    A ball is thrown vertically upwards at 3 m s-1 from 1m above ground level (I) write down the equation for the height of the ball above the ground after t seconds (while the ball is in the air). (II) use your answer to find the time …
  9. Maths

    A ball is thrown vertically upwards at 3 m s-1 from 1m above ground level (I) write down the equation for the height of the ball above the ground after t seconds (while the ball is in the air). (II) use your answer to find the time …
  10. Physics

    A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 9.40 m/s at an angle of 21.0° below the horizontal. It strikes the ground 6.00 s later. (a) How far horizontally from the base of …

More Similar Questions