posted by kgaogelo on .
a bot throws a cricket ball witg an initial velocity of 5m.s from the edge of a tall building.it passes the edge of the building on its way down and strikes the ground below after 5seconds (neglect effects of friction. question1...how does the acceleration of the ball moving downwards compare with the upwards movement?calculate the time taken react the higher point.calculate the height the building.draw a position vs time graph inserting all known values.
V^2 = Vo^2 + 2g*h
h = (V^2-Vo^2)/2g
h = (0-25)/-19.6 = 1.28 m. = Max. ht.
V = Vo + g*t
Tr = (V-Vo)/g = (0-5)/-9.8 = 0.51 s. =
Tf1 = Tr = 0.51 s. = Time to fall back to edge of bldg.
Tf2 = 5 = - Tr - Tf1=5-0.51 - 0.51=3.98 s.
Hb = Vo*t + 0.5a*t^2
Hb = 5*3.98 + 4.9*(3.98)^2 = 97.5 m. =
ht. of bldg.
T = Time in seconds.
h = Ht above gnd. in meters.