A ball is thrown horizontally with speed u from a tower . 4 seconds after the throw its velocity is at 45 degree with horizontal . How long after projection the velocity is at 37 degree with horizontal

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Solution

Dear Student,
$H e r e h o r i z o n t a l v e l o c i t y o f t h e b a l l i s u w h i c h w i l l n o t c h a n g e t h r o u g h o u t t h e m o t i o n b u t v e r t i c a l v e l o c t y w i l l c h a n g e s o v r t i c a l v e l o c i t y a t t = 4 s v = g t = 10 \times 4 = 40 m / s s o \tan (45) = \frac{v e r t i c a l v e l o c i t y}{h o r i z o n t a l v e l o c i t y} = \frac{40}{u} s o u = 40 m / s l e t a f t e r t i m e t v e l o c i t y i s a t 37 t h a n \tan (37) = \frac{v e r t i c a l v e l o c i t y}{h o r i z o n t a l v e l o c i t y} = \frac{g t}{40} t = \frac{3}{4 g} \times 40 = 3 s s o a f t e r 3 s v e l o c i t y i s a t 37$
Regard

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