Question

A boy standing 10 metres from a building can just really reach the roof 12 metre above him when he threw a ball at the optimum angle with respect to the ground. find the initial velocity component of the ball

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Answer 1

Explanation:

h = u^2 sin^2 x°/2g

12 = u^2 sin^2 x° /20

(u sin x°)^2 = 240

u sin x° = 4√15

R/2 = 2UxUy/2g

100 = Ux Uy

Ux = 100/4√15

= 25/√15

initial velocity of the ball is =

= Ux i^ + Uyj^

= 25/√15 i^ + 4/√15 j^