InterviewSolution
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InterviewSolution
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A projectile is fired from the surface of earth of radius `R` with a velocity `k upsilon_(e)` (where `upsilon_(e)` is the escape velocity from surface of earth and `k lt 1)`. Neglecting air resistance, the maximum height of rise from centre of earth isA. `(R )/(k^(2) - 1)`B. `k^(2) R`C. `(R )/(1 - k^(2))`D. `kR` |
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Answer» Correct Answer - C `K_(i) + U_(f) = K_(f) + U_(f)` `(1)/(2) m (k nu_(e))^(2) - (GMm)/(R ) = 0 - (GMm)/(r )` `:. (1)/(2)k^(2) (2gR)- (GM)/(R ) = - (GM)/(r)` or `(GM)/(r ) (1 - k^(2)) = (GM)/(r )` (as `gR = (GM)/(R ))` So, `r = (R )/(1 - k^(2))` |
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