Gravitation

MCQs (Part - VIII)

Question 36: The gravitational force of attraction between two spherical bodies, each of mass 1 kg placed at 10 m apart (G = 6.67 × 10– 11 Nm2 / kg2) is:

  1. 6.67 × 10– 13 N
  2. 6.67 × 10– 11 N
  3. 6.67 × 10– 7 N
  4. none of these

Answer: (a) 6.67 × 10– 13 N

Explanation:

= 6.67 × 10– 13 N

Question 37: If the distance between the two particles is increaseed by 2%, then the force of attraction between them will:

  1. decrease by 6%
  2. decrease by 4%
  3. increase by 4%
  4. increase by 6%

Answer: (b) decrease by 4%

Explanation:

or,

but

Negative sign shows decrease in force of attraction.

Question 38: How the gravitational constant will change if a brass plate is introduced between two bodies?

  1. No change
  2. Decreases
  3. Increases
  4. No sufficient data

Answer: (a) No change

Question 39: Six particles each of mass m are placed at the corners of a regular hexagon of edge length a. If a point mass m0 is placed at the centre of the hexagon, then the net gravitational force on the point mass m0 is:

  3. zero
  4. none of these

Answer: (c) zero

Explanation If equal masses are placed at respectrive corners of a regular polygon, then the gravitational force on a point mass placed at centre of the regular hexagon is zero.

Question 40: Two particles each of mass m are placed at A and C as such AB = BC = L. The gravitational force on the third particle placed at D at a distance L metre on the perpendicular bisector of the line AC, is:

  4. none of these

Answer: (b)

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