posted by micole .
A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 9.50 m/s at an angle of 24.0° below the horizontal. It strikes the ground 5.00 s later.
(a) How far horizontally from the base of the building does the ball strike the ground?
(b) Find the height from which the ball was thrown.
(c) How long does it take the ball to reach a point 10.0 m below the level of launching?
My answers for parts A and B are correct; I can't figure out C.
I tried using the equations delta y= Voy*t + (1/2)g*t^2, using 0 and 9.5sin24 as Voy, but neither worked. I solved the quadratic and got two irrational solutions or times greater than 5 seconds. My last attempt I used t=(2*distance/g)^(1/2)= 1.427seconds; this sounds somwhat logical. Could this be correct?
For (c), did you use -9.8 m/s^2 as the coefficient of t^2? . Did you use -10 m for y? You must consider the upward initial velocity component. Using the quadratic equation, I get a positive root of t=1.87 s.
I did try using both positive and negative g and 10. I also did one positive with one negative; I tried everything. This assignment is online, so I plugged in your answer and that's incorret also. I don't understand, but thanks for the help.