A tower stands at the centre of a circular park. A and B are two points on the boundary of the park such that AB (= a) subtends an angle of 60∘ at the foot of the tower, and the angle of elevation of the top of the tower from A or B is 30∘. The height of the tower is​

Explanation:

answer 1. curved surface separating two media air and glass formula

=Na and Ng

answer 2.radius of curvature approaches to infinity formula

=R/1k

where R is the radius and K is centre of the curvature

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Answer:

Radius of the sphere (r) is (b) 5 cm.

Volume of the half filled cylinder is (c) 1540 cm³.

Volume of sphere is (d) 523.8 cm³.

Volume of the complete filled cylinder is (c) 1.54 litre.

Surface area of the sphere is (a) 314.3 cm².

Given:

Radius of the cylinder (R) = 7 cm

Height of the cylinder (h) = 10 cm

To find:

Radius of the sphere (r).

Volume of the half filled cylinder.

Volume of sphere.

Volume of the complete filled cylinder.

Surface area of the sphere.

Explanation:

We have been given in the question that when a sphere is dropped in a half filled cylinder, the rise in water level is height (h') = 3.4 cm

Solution 1

From Archimedes Principle, we know that the volume of water that will rise in the cylinder, will be equal to the volume of the sphere .

Mathematically,

Volume of water rise  Volume of the sphere

                      πR²h'     4/3 π r³

             Hence,    

Substituting the values, we get

Therefore,

Solution 2

We have the given information, that the cylinder is filled up half.

Hence,      

Therefore,

Volume of the cylinder  πR²H          

Solution 3

We have calculated, radius of the sphere (r) = 5 cm

Therefore,

The volume of the sphere = 4/3 π r³

Substituting the values, we get  

Solution 4

Since, we have height of the full cylinder, that is h = 10 cm

and radius of the cylinder (R) = 7 cm

Therefore, the volume of the cylinder will be = πR²h  

Substituting the given values, we get

Given that,

1 litre = 1000 cm³  ;

Therefore,

1540 cm³ = 1.54 L

Solution 5

We know the surface area of the sphere = 4πr²

where, radius of the sphere r = 5 cm

Hence,

Surface area

Final answer:

Hence,

Radius of the sphere (r) is (b) 5 cm.

Volume of the half filled cylinder is (c) 1540 cm³.

Volume of sphere is (d) 523.8 cm³.

Volume of the complete filled cylinder is (c) 1.54 litre.

Surface area of the sphere is (a) 314.3 cm².

Step-by-step explanation:

Sunita Lyn Williams (née Pandya; born September 19, 1965) is an Indian - American astronaut and United States Navy officer who formerly held the records for most spacewalks by a woman (seven) and most spacewalk time for a woman (50 hours, 40 minutes)...

sorry I don't know urdu....

Answer:

यदि हम बिजली का उपयोग कुशल तरीके से नहीं करते हैं, तो यह एक दिन खत्म हो जाएगा और हम पृथ्वी पर किसी भी तरह से जीवित नहीं रह पाएंगे। बिजली की सुरक्षा के लिए बचत ही एकमात्र रास्ता है, इसलिए सभी मनुष्यों के संयुक्त प्रयासों के लिए जीवन की इस आवश्यक आवश्यकता को संरक्षित करना आवश्यक है।

Explanation: