Question

std 8

Basic Science
1. Find out the odd one in the group and explain what is the common factor in others
a) Distance, Displacement, Velocity, Acceleration
b) mm ,mg ,cm, km
2. Read the following statement carefully and edit it.
a) Unit of speed is *M/S*
b) Unit of force is *Newton*
3.Iron piece of length 200 cm and mass 3000 g is given to you.Rewrite these measurements in to SI unit.
4.We usually extinguish fire using water.But is it possible if petrol or diesel get fire? Why?
5. Consider 'K' as kerosine ,'S' as coloured saline water and 'W' as water.
a) If they all are taken in a bottle,how are they arranged?
b) On which of their quality did you select this answer?
6. What are the uses of friction? Name one solid lubricant to reduce friction.
7. Classify the following into contact and non contact forces.
a) Mango falls down.
b) A box is moved by pulling.
c) A nail is attracted towards a magnet.
8. Write three precautions that a pedestrian should take to avoid a road accident.
9. A car is moving with a velocity of 2 m/s. When the driver applied brake,it come to rest by 4 second.
a) What is the velocity of the car when it come to rest?
b) Calculate the deceleration of the car.
10. A teacher was sitting in a bus. Babu says teacher is at rest and Laila says the teacher is now moving. But when we came to the class, the teacher says both of them are correct.
a) Who among them travelled with the teacher in the bus?
b) Substantiate your answer.
11. What do you mean by the term microne?
12.Given below are certain situations in which variation in pressure is brought about by increasing or decreasing the area of surface. Explain how these are useful.
a)Constructing a knife with the sharp edge.
b) Constructing buildings with wider basements.
c)Making a sewing needle with a sharp tip.​

Answer 1

1. distance is scaler and others are vectors

2. I think it's SI unit. *my guess*

3. 20 m. and 3kg

4. I am not getting your question sry.....

5. a.. from bottom to up. k s w

b. viscosity

6. we walk , we run, whatever we touch it includes friction. talcum powder

7. non contact

contact

non contact

8. I don't know sry

9. 0

-1/2

10. babu

it is like of Einstein frame of reference so babu is sitting inside so according to him she is rest but Laila is outside so for her she is moving.

11. 1 of 1 million

12. helps in making more pressure

helps in making less pressure to ground.

helps in making more pressure.