A man is walking towards a vertical pillar in | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Let $PQ$ represent the pillar with height $h$.In $\Delta PAQ$,$	an(30^o) = \frac{PQ}{AQ}$ $\Rightarrow \frac{1}{\sqrt{3}} = \frac{h}{AQ}$ $\Right

Vedclass · Accepted Answer

$5$

Vedclass · Answer

(B) Let $PQ$ represent the pillar with height $h$.In $\Delta PAQ$,$	an(30^o) = \frac{PQ}{AQ}$ $\Rightarrow \frac{1}{\sqrt{3}} = \frac{h}{AQ}$ $\Rightarrow AQ = h\sqrt{3}$.In $\Delta PQB$,$	an(60^o) = \frac{PQ}{BQ}$ $\Rightarrow \sqrt{3} = \frac{h}{BQ}$ $\Rightarrow BQ = \frac{h}{\sqrt{3}}$.The distance covered in $10 	ext{ minutes}$ is $AB = AQ - BQ = h\sqrt{3} - \frac{h}{\sqrt{3}} = \frac{3h - h}{\sqrt{3}} = \frac{2h}{\sqrt{3}}$.Since the speed is uniform,the time taken is proportional to the distance.Time taken to cover $AB = 10 	ext{ minutes}$.Time taken to cover $BQ = \frac{BQ}{AB} 	imes 10 = \frac{h/\sqrt{3}}{2h/\sqrt{3}} 	imes 10 = \frac{1}{2} 	imes 10 = 5 	ext{ minutes}$.

Similar Questions

The shadow of a tower standing on a level ground is found to be $60 \ m$ longer when the Sun's altitude is $30^{\circ}$ than when it is $45^{\circ}$. The height of the tower is

The angle of elevation of a jet plane from a point $A$ on the ground is $60^{\circ}$. After a flight of $20 \, s$ at the speed of $432 \, km/h$, the angle of elevation changes to $30^{\circ}$. If the jet plane is flying at a constant height, then its height is ..... $m$. (in $\sqrt{3}$)

Two vertical poles are $150 \ m$ apart and the height of one is three times that of the other. If from the middle point of the line joining their feet,an observer finds the angles of elevation of their tops to be complementary,then the height of the shorter pole (in meters) is

$A$ flag-post $20 \ m$ high standing on the top of a house subtends an angle whose tangent is $\frac{1}{6}$ at a distance $70 \ m$ from the foot of the house. The height of the house is......$m$

From a point on the level ground, the angle of elevation of the top of a pole is $30^{\circ}$. On moving $20 \ m$ nearer to the pole, the angle of elevation becomes $45^{\circ}$. The height of the pole (in metres) is:

Vedclass Test Series

Exam Paper Generator

Online Exam Module