An electrician has to repair an electric fault on a pole of height $5\, m$. She needs to reach a point $1.3\, m$ below the top of the pole to undertake the repair work (see figure). What should be the length of the ladder that she should use which,when inclined at an angle of $60^{\circ}$ to the horizontal,would enable her to reach the required position? Also,how far from the foot of the pole should she place the foot of the ladder? (You may take $\sqrt{3}=1.73$)

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) In the figure,the electrician is required to reach the point $B$ on the pole $AD$.
So,
$BD = AD - AB = (5 - 1.3)\, m = 3.7\, m$
Here,$BC$ represents the ladder. We need to find its length,i.e.,the hypotenuse of the right triangle $BDC$.
Now,we consider the trigonometric ratio $\sin 60^{\circ}$.
So,$\frac{BD}{BC} = \sin 60^{\circ}$ or $\frac{3.7}{BC} = \frac{\sqrt{3}}{2}$
Therefore,$BC = \frac{3.7 \times 2}{\sqrt{3}} = \frac{7.4}{1.73} \approx 4.28\, m$.
i.e.,the length of the ladder should be $4.28\, m$.
Now,$\frac{DC}{BD} = \cot 60^{\circ} = \frac{1}{\sqrt{3}}$.
i.e.,$DC = \frac{3.7}{\sqrt{3}} = \frac{3.7}{1.73} \approx 2.14\, m$.
Therefore,she should place the foot of the ladder at a distance of $2.14\, m$ from the pole.

Explore More

Similar Questions

$A$ tree breaks due to a storm and the broken part bends so that the top of the tree touches the ground,making an angle of $30^{\circ}$ with it. The distance between the foot of the tree and the point where the top touches the ground is $8\, m$. Find the height of the tree.

Two poles of equal heights are standing opposite each other on either side of the road,which is $80\, m$ wide. From a point between them on the road,the angles of elevation of the top of the poles are $60^{\circ}$ and $30^{\circ},$ respectively. Find the height of the poles and the distances of the point from the poles.

Difficult
View Solution

An observer $1.5\, m$ tall is $28.5\, m$ away from a chimney. The angle of elevation of the top of the chimney from her eyes is $45^{\circ}$. What is the height of the chimney? (in $m$)

The angles of elevation of the top of a tower from two points at a distance of $4 \,m$ and $9 \,m$ from the base of the tower and in the same straight line with it are complementary. Prove that the height of the tower is $6 \,m$.

From a point $P$ on the ground,the angle of elevation of the top of a $10 \, m$ tall building is $30^{\circ}$. $A$ flag is hoisted at the top of the building and the angle of elevation of the top of the flagstaff from $P$ is $45^{\circ}$. Find the length of the flagstaff and the distance of the building from the point $P$. (You may take $\sqrt{3} = 1.732$)

Difficult
View Solution

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo