Question

1. Which force keep the moon going around the Earth. Who provides this force? What would have happened in the absence of such a force? 2. A falling apple attracted towards the earth. Then why don’t we see the earth moving towards the apple? 3. What happens to the force of attraction between two objects when (i) Their mass are halved? (ii) Distance between them is increased to 4 times its previous value. (iii) Distance between them as well as each of the mass is increase to 4 times. 4. If the distance between two bodies is increased 4 times by what factor should the mass of the bodies be altered so that the gravitational force between them remains the same? 5. What is the force between two spheres weighing 20 kg each and placed 50 cm apart? 6. A sphere of mass 40 kg is attracted by another sphere of mass 15 kg when their centres are 0.2m apart with force of 9.8 x 10-7 N. Calculate value of ‘G’. 7. Why don’t we see objects in the universe colliding or moving towards each other due to gravitational force? 8. Calculate the gravitational force between a body of mass 100 kg and the earth. Also calculate the acceleration produced in the body and that in earth. 9. A body weighs 1 kg on the surface of the moon. If mass of the moon is 7.4 x 10 22 kg and radius of moon is 1740 km. Calculate: a. The force acting between the body & the moon. b. Acceleration produced in the body c. Acceleration produced in moon. 10. A planet has mass and radius 1/3 of those of earth. Calculate the acceleration due to gravity of the planet and compare it with acceleration due to gravity on earth. If an object has 5 kg mass on earth. Calculate its weight on the planet. 11. A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate: i. the max height to which it rises. (ii) total time it takes to return to surface of the earth. 12. A stone is released from the top of a tower of height 19.6 m. Calculate the final velocity of a body just before touching the ground. 13. A stone is thrown vertically upwards with an initial velocity of 40m/s. Find the max height reached by the stone. What is the net displacement and the total distance covered by the stone? [g = 10m/s2] 14. The object dropped from a height (h) with initial velocity zero strikes the ground with a velocity of 30m/s. How long does it take to reach the ground. Also find h [g = 10m/s2] 15. The mass of a man is 75 kg. What will be his weight on surface of earth? What will be his weight on surface of moon? 16 the gravitational force between sun and Jupiter is approximately 4x10 23N. if the mass of the sun= 1.99x1030 kg, the mean distance of the Jupiter from the sun is 7.8x1011 m find the mass of Jupiter. 17. A particle is thrown up vertically with a velocity of 50m/s. What will be the velocity at the highest point of its journey? How high the particle would rise? What time would it take to reach the highest point? 18. A ball is dropped from the top of a tower 40m high. What is its velocity when it has covered 20m? What would be its velocity when it hits the

Answer 1

1 gravitational force.Sun provides this force. In absence of this force planets would not revive in there own orbits and may collide.
2. gravitational force is proportional to mass. Mass of earth is very big compared to the Apple that's why we don't see Apple going towards Apple.
3 force reduces by 1/6 of actual force.

Answer 2

Answer:

Centripetal force

Force of attraction

planet's would be collided