Very Short Answer Questions - 1 Mark

Q1. What will happen to the gravitational force between two bodies if the masses of one body is doubled?

Ans. If the mass of one body is doubled, force is also doubled.

Q2. Why is 'G' called the universal gravitational constant?

Ans. The constant G' is universal because it is independent of the nature and sizes of bodies, the spare where they are kept and at the time at which the force is considered.

Q3. who formulated the universal law of gravitation?

Ans. Isaac Newton

Q4. How is gravitation different from gravity?

Ans. Gravitation is the force of attraction between any two bodies while gravity refers to attraction between any body and the earth.

Q5. What does a small value of G indicate?

Ans. A small value of G indicates that the force of gravitational attraction between two ordinary size objects is a very weak force.

Q6. At what place on the earth's surface is the weight of a body maximum?

Ans. At the poles.

Q7. At what place on the earth's surface is the weight of a body minimum?

Ans. At the equator.

Q8. If the mass of a body is 9.8 kg on the earth, what would be its mass on the moon?

Ans. It will remain the same on the moon, i.e., 9.8 kg.

Q9. Do fluids possess weight?

Ans. Yes, fluids have weight.

Q10. Why can one jump higher on the surface of the moon than on the earth?

Ans. Because the value of acceleration due to gravity (g) on the moon's surface is nearly 1/6th to that the surface of the earth.

Q11. Define the standard kilogram.

Ans. The standard kilogram is the mass of a block of a platinum alloy kept at the international bureau of weights and measures near Paris in France.

Q12. If the earth attracts two objects with equal force, can we say that their masses must be equal?

Ans. No

Q13. Is weight a force?

Ans. Yes.

Q14. What keeps the moon in uniform circular motion around the earth?

Ans. Gravitational force between moon and the earth keeps moon in uniform circular motion around the earth.

Q15. When a body is dropped from a height, what is its initial velocity?

Ans. Zero.

Q16. When a body is thrown vertically upwards, what is its final velocity?

Ans. Zero.

Q17. Is the time taken by a body to rise to the highest point equal to the time taken to fall from the same height?

Ans. Yes.

Q18. Is the acceleration due to gravity acting on a freely falling body directly proportional to the (a) mass of the body? (b) time of fall of the body?

Ans. (a) No           (b) No

Q19. Suppose gravity of earth suddenly becomes zero, then which direction will the moon begin to move if no other celestial body affects it?

Ans. The moon will begin to move in a straight line in the direction in which it was moving at that instant because the circular motion of moon is due to centripetal force provided by the gravitational force of the earth.

Q20. The earth is acted upon by gravitation of sun, even though it does not fall into the sun. Why?

Ans. The gravitational force is responsible for providing the necessary centripetal force which allows the earth to move around the sun at the defined path or orbit. So, the earth does not fall into the sun.

Q21. If the small and big stones are dropped from the roof of a house simultaneously, they will reach the ground at the same time. Why?

Ans. The acceleration due to gravity does not depend upon the mass of the stone or body. Both the bodies fall with the same acceleration towards the surface of the earth. Thus a big stone will fall with the same acceleration as a small stone. So, both the stones will reach the ground at the same time when dropped simultaneously.