Q32 of 43 Page 85

From the top of a tower 19.6m high a ball is thrown horizontally. If the line joining the point of projection to the point where it hits ground makes an angle of 45° with the horizontal then initial velocity of ball is:

a) 9.8 ms–1


b) 4.9 ms–1


c) 14.7 ms–1


d) 2.8 ms–1

let initial velocity of the ball = u


ux = initial velocity along x axis = u


uy = final velocity along y axis = 0


let t = time of flight


Considering Y components,



sy = 19.6m


uy = 0 m/s


ay = g


t = T






Considering X components



sx = 19.6 tan(45o) = 19.6


ux = u


ax = 0


t = T = 2 s





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