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Question
There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.
- Find the area of lake B on the drawing in square cm. What is its actual area in square km?
Solution
Lake B has 15 fully filled squares and 11 half-filled or more than half-filled squares.
- Area of 15 fully filled squares
= 15 × 15
= 225 square cm
We consider the area of every single half-filled or more than half-filled square as 1-centimetre square.
- Thus, the area of 11 such squares
= 11 × 11
= 121 square cm - So, the total area of lake B
= 225 + 121
= 346 square cm
We are given 1 cm on drawing = 1 km on the ground
Therefore, 346 square cm on drawing = 346 km
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Answer the following question.
Star A is farther than star B. Which star will have a large parallax angle?
Match the following.
| 1. | Length of the fore arm | metre |
| 2. | SI unit of length | second |
| 3. | Nano | 103 |
| 4. | SI Unit of time | 10–9 |
| 5. | Kilo | Cubit |
Find the answer for the following questions within the grid.
- 10-3 is one ______
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- ______ is the amount of substance present in an object.
- ______ can be taken to get the final reading of the recordings of different students for a single measurement.
- ______ is a fundamental quantity.
- ______ shows the distance covered by an automobile
- A tailor uses ______ to take measurements to stitch the cloth.
- Liquids are measured with this physical quantity.
Can you find the diameter of a thin wire of length 2 m using the ruler from your instrument box?
Guess whose tail is the longest. Now measure the tails. How good is your guess?
What is Dinesh’s height in metres? _____ m _____ cm.
Measure the yellow rectangle. It is ________ cm long.
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How close was your earlier guess? Discuss.
Can you think of how to cut a postcard so that you can pass through it?
You can play this game on the ground. Make two squares of one square meter each. Divide your class into two teams. Ready to play!
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So Anar also tried many different ways to make a boundary for 800 square meters of land.
He made rectangles A, B, and C of different sizes. Find out the length of the boundary of each. How much gold wire will he get for these rectangles?
- A
Gold wire for A = _________ metres - B
Gold wire for B = _________ metres - C
Gold wire for C = __________ metres
But then Anar made an even longer rectangle... See how long!
- D
So he will get __________ metres of gold wire!!
Length is a fundamental quantity.
What is the unit of length?
The SI unit of mass is kg.
- The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
- Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
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