# CBSE Important Questions(Short questions) for Gravitation

Given below are the Class 9 Science Important Questions for CBSE Important Questions(Short questions) for Gravitation
a) Concepts questions
b) Calculation problems
c) Multiple choice questions
e) Fill in the blank's
1. State Archimedes’ principle?
2. Define buoyancy. State the factors on which buoyant force depends?
3. What do you understand by 1 Pascal and 1 Newton?
4. Define thrust. A force of 150N acts on a surface of area 15cm2. Calculate thrust and pressure?
5. If a fresh egg is put into a beaker filled with water, it sinks. On dissolving a lot of salt in the water, the egg begins to rise and then floats. Why?
6. Define pressure? Give its mathematical expression and its SI unit?
7. In what direction does the buoyant force on an object immersed in a liquid act?
8. Differentiate between density and relative density?
9. Relative density of gold is 19.3. The density of water is 1000kg/m3. Find the density of gold in SI unit in g/cc?
10. State the conditions under which a body will sink or float in a fluid?

11. How do snow shoes stop you from sinking into snow?
12. A child sitting along a swimming pool feels lighter while lowering his legs in water. Why?
13. Relative density of silver is 10.8? What is the density of silver in SI unit?
14. a block of wood of mass 5kg and dimensions 40cm*25cm*10cm is placed on a table top. Find the pressure exerted if the block lies on the table top with sides of dimension:
a) 10cm*25cm
b) 40cm*10cm
15. Define relative density. Relative density of mercury is 13.6. The density of water is 103kg/m3. What is the density of mercury in SI unit?
16. You are provide with a hollow iron ball of volume 20cm3, mass of 15g and a solid iron ball of mass 20g. Both are placed on the surface of water contained in a large tub. What will float? Give reason for your answer?
17. The dining has dimensions 50m*15m*3.5m. Calculate the mass of air in the hall? (Density of air= 1.30kg/m)?
18. Find the ratio of the pressure exerted by a block of 400N when placed on a table top along its two different sides with dimensions 20cm*10cm and 10cm*15cm.
19. A force of 100N acts on a surface of area 25m2? Calculate thrust and pressure. Calculate the changed pressure if the force now is reduced to 25N?
20. If two forces in the ratio 5:7 act on two areas in the ratio 4:5, Find he ratio of pressure exerted?
21. Define thrust? Name the factors on which the pressure depends. If a man standing on a sand surface lies down on the sand, how will the pressure exerted on sand by the man be affected in two positions?
22. Mass of body ‘A’ is equal to mass of body ‘B’. If the density of body ‘A’ is greater than the density of body ‘B’, which is easier to lift through air?
23. Why does a body lose weight when immersed in a liquid?