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CBSE Class 9 - Physics -Gravitation and Flotation (Solved Numerical Problems)

**Questions:**
1) Find the total thrust acting on the bottom surface of a tank 4m long, 2m broad and 2m deep when fully filled with water. The density of water= 10³ kg/m³.

2) The gravitational force between two objects is 100N. How should the distance between the objects be changed so that force between them becomes 50N?

3) If the distance between two masses be increased by a factor of 6, by what factor would the mass of one of them have to be altered to maintain the same gravitational force? Would this be an increase or decrease in the mass?

4) The value of ‘g’ on earth’s surface is 9.8 m/s². Suppose the earth suddenly shrinks to one-third of its present size without losing any mass. What is the value of ‘g’ on the surface of shrunk earth?

5) Two bodies of mass 1kg and 100kg respectively are dropped simultaneously from same height 4.9m in a vacuum. Calculate and compare their final velocities just before hitting the ground and the time interval in which they will hit the ground.

6) The ratio of gravitational force on Neptune to the gravitational force on earth is 9:8. Ramesh weighs 792N on earth. Calculate his weight on Neptune.