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Case Study - 1
Kite festival is a popular festival in India which takes place during Makar Sankranti. The festival is celebrated by people flying kites from their rooftops. Reena and Ravi are also flying kites to enjoy the festival. The height of Reena's kite is $60$ m above the ground. The string attached to the kite is temporarily tied to a point on the ground, and the inclination of the string with the ground is $30^\circ$. Ravi is flying a kite from a $10$ m high building. His kite is also flying $60$ m above the ground and the length of the string used by Ravi is same as that of Reena's. $\theta$ is the angle of elevation of Ravi's kite from a point on the rooftop.
Based on the above information, answer the following questions :
(i) Find the length of string used by Reena.
(ii) Find the value of $\sin \theta$.
(iii) (a) If $\theta$ changes to $60^\circ$, without changing the length of the string, what will be the height of Ravi's kite above the ground ? (Use $\sqrt{3} = 1.7$)
OR
(b) What would have been the height of Ravi's kite above the ground, if the string had an inclination of $30^\circ$ with the ground, assuming that the length of the string does not change ?
Kite festival is a popular festival in India which takes place during Makar Sankranti. The festival is celebrated by people flying kites from their rooftops. Reena and Ravi are also flying kites to enjoy the festival. The height of Reena's kite is $60$ m above the ground. The string attached to the kite is temporarily tied to a point on the ground, and the inclination of the string with the ground is $30^\circ$. Ravi is flying a kite from a $10$ m high building. His kite is also flying $60$ m above the ground and the length of the string used by Ravi is same as that of Reena's. $\theta$ is the angle of elevation of Ravi's kite from a point on the rooftop.
Based on the above information, answer the following questions :
(i) Find the length of string used by Reena.
(ii) Find the value of $\sin \theta$.
(iii) (a) If $\theta$ changes to $60^\circ$, without changing the length of the string, what will be the height of Ravi's kite above the ground ? (Use $\sqrt{3} = 1.7$)
OR
(b) What would have been the height of Ravi's kite above the ground, if the string had an inclination of $30^\circ$ with the ground, assuming that the length of the string does not change ?
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Solution: (i) $\frac{60}{l} = \sin 30^\circ \Rightarrow l = 120$ m [1 mark]
(ii) $\sin \theta = \frac{50}{120}$ or $\frac{5}{12}$ [1 mark]
(iii) (a) $\frac{x}{120} = \sin 60^\circ \Rightarrow x = 60\sqrt{3}$ [1 mark]
$\text{Height of Ravi's kite} = 60\sqrt{3} + 10$ [1/2 mark]
$= 102 + 10 = 112$ m [1/2 mark]
OR
(iii) (b) $\frac{x}{120} = \sin 30^\circ \Rightarrow x = 60$ m [1 mark]
$\text{Height of Ravi's kite} = 60 + 10 = 70$ m [1 mark]
(ii) $\sin \theta = \frac{50}{120}$ or $\frac{5}{12}$ [1 mark]
(iii) (a) $\frac{x}{120} = \sin 60^\circ \Rightarrow x = 60\sqrt{3}$ [1 mark]
$\text{Height of Ravi's kite} = 60\sqrt{3} + 10$ [1/2 mark]
$= 102 + 10 = 112$ m [1/2 mark]
OR
(iii) (b) $\frac{x}{120} = \sin 30^\circ \Rightarrow x = 60$ m [1 mark]
$\text{Height of Ravi's kite} = 60 + 10 = 70$ m [1 mark]