Olympiad – Class IX – Science - Phy - Gravitation and Pressure

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Question - 1

A body weighs 72 N on the surface of the earth. What is the gravitational force on it at a height equal to half the radius of the earth from the surface

  • A 72 N
  • B 28 N
  • C 16 N
  • D 32 N

Question - 2

Where will it be profitable to purchase one kilogram sugar?

  • A At the poles
  • B At the equator
  • C At 45° latitude
  • D At 40° latitude

Question - 3

The figure given below shows a planet in elliptical orbit around the sun S.

At what position will the kinetic energy of the planet be maximum?

  • A P1
  • B P4
  • C P3
  • D P2

Question - 4

If the mass of a body is M on the surface of the earth, what would be the mass of the same body on the surface of the moon?

  • A M/6
  • B Zero
  • C M
  • D 2 M

Question - 5

Find the gravitational attraction between the two atoms in a hydrogen molecule when G is 6.67 X 10-11 Nm2 kg-2 mass of a hydrogen atom is 1.67 x 10-27 kg and distance between the two atoms is 1 A.

  • A 11.14 x 10-18 N
  • B 2.39 x 10-45 N
  • C 1.86 X 10-44 N
  • D 4.18 x 10-23 N

Question - 6

The distances of two planets (Neptune and Saturn) from the sun are 1013 m and 1012 m respectively. Find the ratio of the time periods of the planets.

  • A \(100:1\)
  • B \(1:\sqrt { 10 } \)
  • C \(\sqrt { 10 } :1\)
  • D \(10\sqrt { 10 } :1\)

Question - 7

When does the value of g at a place increase?

  • A With decrease in the latitude of the place
  • B With increase in the latitude of the place
  • C With increase in the altitude of the place
  • D With increase in the angular rotation of the earth

Question - 8

Two planets A and 8 have their radii in the ratio of 2: 5 and densities in the ratio of 1: 6 respectively which of the following statements is NOT true regarding the given information?

  • A The ratio of acceleration due to gravity on them is 1 : 15
  • B For the same volume of planets, mass of planet A is greater than that of planet 8
  • C A body weighs 15 times more on planet 8 than on planet A
  • D Planet 8 has greater volume than planet A

Question - 9

Which of the following statements is NOT correct about a planet rotating around the sun in an elliptical orbit?

  • A Its kinetic energy is constant.
  • B Its angular momentum is constant.
  • C Its areal velocity is constant.
  • D Its time period is proportional to r3

Question - 10

Two spheres each of mass 105 kg and radius 10m are kept in contact. Find the force of gravitation acting between them.

  • A 10-3 N
  • B 6.67 x 10-3N
  • C 6.67 x 10-11 N
  • D 10-11 N