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 The position of a projectile launched from the origin at t=0 is given by

\vec{r}= \left ( 40\hat{i} +50\hat{j}\right )m   at t = 2s.

If the projectile was launched at an angle \Theta from the horizontal, then \Theta is (take g=10 ms-2).

 

 

Option: 1

tan ^{-1}\: 2/3


Option: 2

tan ^{-1}\: 3/2


Option: 3

tan ^{-1}\: 7/4


Option: 4

tan ^{-1}\: 4/5


Answers (1)

best_answer

Using 

S=ut+\frac{1}{2}at^2

u Cos\theta\times t+ \frac{1}{2}(0)t^{2}=\:u t\:\:\:\:\:\:\:\:\:\ \because g=0

u Cos\theta.t=40

(u Cos\theta) (2)=40

u Cos\theta = 20 -------- (1)

u Sin\theta t - \frac{1}{2}\:gt^{2}=50

(u Sin\theta \times 2)-(\frac{1}{2}\times10\times4)=50

u Sin\theta=35----------(2)

From equation (1) and (2)

\theta = tan^{-1}(\frac{7}{4})

Posted by

shivangi.bhatnagar

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