Question

a ball is projected from ground @ an angle 45' with the horizontal frm a distance d1 frm thefoot of a pole and just after touching the top of pole it falls on ground @ distance d2 from pole on other side,the height of pole is??

Answer 1

Use eqation of projectile and range R= d1+d2 u will find height of pole in terms of d1 and d2

Answer 2

did,the answer is coming (d1+d2)/4..but the answer is d1d2/(d1+d2)

Answer 3

yup second one is right

Answer 4

mines not coming.

Answer 5

From equation of trajectory
[[y= x \tan \theta -\frac{ 1 }{ 2 }\frac{ gx ^{2} }{ u ^{2}\cos ^{2}\theta }\]
u will get y height of pole by putting x= d1 which will come in term of u so u have to find u by puting R= d1 +d2 in range formula and put u in above eqn

Answer 6

i was doing by wrong process,thank you.

Answer 7

\[y= x \tan \theta -\frac{ 1 }{ 2 }\frac{ gx ^{2} }{ u ^{2}\cos ^{2}\theta }\]

Answer 8

yeah,get it.i think it would be easier if we put,
\[y=x(1-x/R)\tanalpha\]

Answer 9

yupp u got it.