Posted by Anonymous on .
A ball is thrown from the window of a highrise building with an initial velocity of 7.7 m/s at an angle of 34 deg. below the horizontal. The bill strikes the ground 4.2 seconds after being thrown. Find the height from which the ball was thrown.

physical 
drwls,
y = H 7.7 sin34 t  4.9 t^2.
y = 0 at t = 4.4 s
Substitute those y and t values into the first equation and solve for the initial height H