Gravitation

MCQs (Part - III)

Question 11: The radius of the earth shrinks by 1%. the acceleration due to gravity on the earth's surface would : (mass remaining constant)

  1. increase by 2%
  2. increase by 1%
  3. decrease by 1%
  4. decrease by 0.5%

Answer: (a) increase by 2%

Question 12: If F1 is the magnitude of the force exerted on earth by moon and F2 is the magnitude of force exerted on moon by earth then:

  1. F1 > F2
  2. F1 = F1
  3. F1 < F2
  4. none of these

Answer: (b)F1 = F1

Question 13: The gravitational force of atteraction between two spherical bodies, each of mass 100 kg, if the distance between their centres is 100 m, is : (G = 6.67 × 10– 11 Nm2 kg– 2)

  1. 6.67 × 10– 11 N
  2. 6.67 × 10– 9 N
  3. 6.67 N
  4. none of these

Answer: (a) 6.67 × 10–11 N

Explanation:

Question 14: A particle is fired vertically upwards with a speed of If the radius of the earth is R then the maximum height attainded by the particle will be:

  1. R
  2. 2 R
  3. 3 R
  4. 4 R

Answer: (d) 4 R

Explantion:

Question 15: A planet has radius and mass, both half of those of the earth, then the value of g on that planet will be:

  1. 4.9 m/s2
  2. 9.8 m/s2
  3. 19.6 m/s2
  4. 13.8 m/s2

Answer: (c) 19.6 m/s2

Explantion:

So,

gp = 2ge = 2 × 9.8 = 19.6 m/s2

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