Question

SECTION

V. Answer the following questions
10x330
1. Categorise the materials of the following products into 'can be recycled and cannot be recych
Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastic bowls.pl
covering on electrical wires, plastic chairs, electrical switches
2. Give two differences between a yote and a foetus
3. What is called as rolling friction?
4. A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting
rocket immediately after leaving the launching pad
5. Explain why sliding friction is less than static friction?
6. What is fertilization? How many types of fertilization do you know?
7. Explain why some fibres are called synthetic
8. Give two examples of situations in which applied force causes a change in the shape of an obj
9. Give examples to show that plastics are non corrosive in nature
10. What is meant by viviparous animals? Give two examples
SECTION
1. Friction is both a friend and foe Give examples to support this statement
2. Draw a neat labeled diagram of female reproductive organs in humans
3. Avoid plastics as far as possible. Comment on this advice
4. Why do fish and frogs lay eggs in hundreds whereas a hen lays only one egg at a time?​

Answer 1

Answer:

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1) Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastics bowls, plastics covering on electrical wires, plastics chairs, and electrical switches. Ans. Recyclable: Toys, carry boys, cooker handles, ball point pen, plastic chairs, electric wire Rest can't be recycled. 9.

2) The zygote is the initial stage in baby development.

Difference between and Zygote and Foetus.

Zygote Foetus

It is formed by the fusion of the nuclei of the sperm and egg. It is the stage of the embryo which nearly resembles a human being.

It is a unicellular structure. It is a multicellular structure.

3) Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. Another cause of rolling resistance lies in the slippage between the wheel and the surface, which dissipates energy.

4) The two forces acting on the rocket immediately after leaving the launching pad are gravitational force and frictional force. The gravitational force acts downwards towards the earth and frictional force acts due to surrounding air.

5) During sliding, contact points do not get enough time to get interlocked properly. Therefore, less friction. But, when the object is at rest, the surfaces interlock well, therefore friction is more. This explains why sliding friction is less than static friction.

6) But the fusion of gametes may take place inside or outside the body. Based on this, fertilization is of two types – internal and external fertilization.

7) Some fibres are called as synthetic fibers because these are manmade fibers prepared by using chemicals. These are made of small units that join together to form long chains.

8) Two examples of forces that cause a change in the shape of an object are as follows: Squeezing of a plastic bottle changes the shape of the bottle. Deformation of clay by pressing it between the hands.

9) Synthetic Fibres and Plastics

Following examples show that plastics are non-corrosive in nature : (i) They are used to store chemicals. For example cleansing chemical are very reacticve and store in plastic bottle. (ii) They are used to store all types of food, as it does not react to materials stored in it.

10) In the viviparous type of animals, females can give birth to young ones. Mammals (except egg-laying mammals), like whale, shark, mouse, humans are examples of viviparous animals. Frog is an oviparous animal. The butterfly is an oviparous animal. So, the correct answer is Human being.

Section 2

1) (i) Friction allows us to grip and catch different objects.

(ii) It helps us to walk comfortably on the surface.

(iii) It helps to minimise the speed or to stop the moving objects.

(iv) It helps us to write on paper or blackboard.

(v) The things do not move from their places due to friction.

Friction is foe (Disadvantages) :

(i) Friction causes wear and tear in objects.

(ii) It causes damage the parts of machines.

(iii) The machines or tools require regular maintenance due to which a lot of money is wasted.

(iv)It reduces the speed of moving objects so more force is required.

(v)It does not allow the free movement of objects.

2) The female reproductive structure consists of a pair of ovaries, uterus, fallopian tubes, cervix and vagina. The ovary is a paired structure, located in the upper pelvic cavity. It is shaped like an almond, size is around 3.5 cm to 2 cm wide, 1 cm thick. Each ovary releases one egg cell once a month simultaneously.

Diagram is in the image above...

3) Plastics are non-biodegradable materials. So use of plastics is harmful for our environment. The plastics cannot be finally disposed off. Thus, plastics should be avoided as far as possible.

4) Hence, very few new frogs are produced. Whereas, in case of a hen, internal fertilization takes place and hence the survival of the baby which would hatch from the egg has much higher rates of survival as compared to those in case of a frog. Hence, hen produces only one egg.

Answer 2

Answer:

nai nai nai nai nai

Explanation: