1.

Two bodies are projected from the same points withequal speeds in such directions that they both strike the same point on a plane whose inclination is beta. If alpha be the anlge of projection of the first body with the horizontal show that the ratio of their times of light is (sin(alpha-beta))/(cos alpha)

Answer»

SOLUTION :Let `alpha` be the ANGLE of projection of the second body
`R=(u^(2))/(g cos^(2)BETA)[sin(2 alpha-beta)-sin beta]`
Range of both the bodies is same, therefore
`sin (2alpha-beta)=sin(2 alpha.-beta)` or `sin 2 alpha.-beta=pi-(2alpha-beta)`,

`alpha.=(pi)/2-(alpha-beta)`
Now `T=(2U sin (alpha-beta))/(g cos beta)` and `T.=(2u sin (alpha.-beta))/(g cos beta)`
`:.T/(T.)=(2SIN (alpha-beta))/(2sin (alpha.-beta))=(sin(alpha-beta))/(sin{(pi)/2-(alpha-beta)-beta})`
`sin=((alpha-beta))/(sin((pi)/2-alpha))=(sin(alpha-beta))/(cos alpha)`


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