Question
A boat is being rowed away from a cliff 183 m high. From the top of the cliff, the angle of depression of the boat changes from 60° to 45° in 3 minutes. What is the speed of the boat?(approx.)
According to the figure above: Cot 45° = (AD/AB) = 1= (AD/183) = 183 m Also, Cot 60° = (AC/AB) = (1/ √3 ) = (AC/150) = AC = (183/√3 ) m Therefore AC = (183 x √3 )/(√3 x √3) = 61√3 = 61 x 1.73 = 105.5 m Therefore CD = AD - AC = (183 - 105.5) = 77.5 m Speed of Boat = 77.5/180 m/s ((77.5/180) x (18/5) ) km/hr (1395/900) = 1.5km/hrMore Height and Distance Questions
- From the top of a tower, the angle of depression of a car on the ground is 30°. After the car moves 40 m towards the tower in a straight line, the angle of...
- From the top of a straight pillar 20 meters high, the angle of elevation of the top of a straight tower was 45°. If the tower was 70 meters high, then at w...
- The angle of elevation of the top of a building from a point on the ground is 30° and moving 40 meters towards the building it becomes 60°. The height of t...
- The angle of elevation of the top of a building from a point on the ground is 30° and moving 40 meters towards the building it becomes 60°. The hei...
- Two buildings are collinear with the base of a tower and are at a distance 9m and 16m from the base of the tower. The angles of elevation from these two bu...
- A long metallic cable is stretched from a point P on the ground to the top of a cliff, forming an angle of 30 ° with the horizontal ground. The total lengt...
- The angle of depression of a point on the ground as seen from the top of a tower, 25 feet high, is 45°. Find the distance of the point on the ground from t...
- From the top of a lighthouse, the angle of depression to the top and bottom of a tower is 30° and 45°, respectively. If the lighthouse is 210 metre...
- From a watch tower of 150 m height, the angles of depression of two cliffs in a horizontal line through the base of the tower are 45° and 30°. Find the dis...
- From a point on the ground, the angle of elevation of the top of a tower is 45 degrees. After moving 20 m away from the tower, the angle becomes 30 degree...
Hey! Ask a query
Please enter email id
The email must be a valid email address.
Please enter Mobile Number
Please enter valid Mobile Number
Please enter your Doubt
