9th Class Science Gravitation and Floatation Question Bank

done Gravitation Conceptive Objective Problems Total Questions - 12

• question_answer1)
                                  The gravitational force of attraction between two spherical bodies, each of mass 1kg placed at 10m apart is:
  A)
   \[\text{6}.\text{67}\times \text{1}{{0}^{-\text{13}}}\text{ N}\]         done clear
  B)
   \[\text{6}.\text{67}\times \text{1}{{0}^{-11}}\text{ N}\] done clear
  C)
   \[\text{6}.\text{67}\times \text{1}{{0}^{-\text{7}}}\text{ N}\]                   done clear
  D)
   \[\text{6}.\text{67}\times \text{1}{{0}^{-4}}\text{ N}\] done clear
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• question_answer2)
  A sphere of mass 40 kg is attracted by a second sphere of mass 60 kg with a force equal to\[4\times {{10}^{-5}}N\].If\[G=6\times {{10}^{-11}}N{{m}^{2}}/k{{g}^{2}},\] calculate the distance between the two spheres.
  A)
   3 cm.                    done clear
  B)
   6 cm. done clear
  C)
   9 cm.                    done clear
  D)
   10 cm. done clear
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• question_answer3)
  When a space ship is at a distance equal to two earth's radius from the centre of the earth, the gravitational acceleration is
  A)
   \[\text{19}.\text{6 m}/{{\text{s}}^{\text{2}}}\]                 done clear
  B)
   \[\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}}\] done clear
  C)
   \[\text{4}.\text{9 m}/{{\text{s}}^{\text{2}}}\]                   done clear
  D)
   \[\text{2}.\text{45 m}/{{\text{s}}^{\text{2}}}\] done clear
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• question_answer4)
  Masses of the earth and the moon are in the ratio of 3 : 2 and the radii of the earth and the moon are in the ratio of 6 : 1. The ratio of the weight of the body on their surfaces will be
  A)
   \[\frac{1}{12}\]                                done clear
  B)
   \[\frac{1}{24}\] done clear
  C)
   \[\frac{12}{1}\]                                done clear
  D)
   \[\frac{24}{1}\] done clear
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• question_answer5)
  Two planets have radii r and 2r and densities are d and 4d respectively. The ratio of their acceleration due to gravities is
  A)
   1 : 8       done clear
  B)
   8 : 1   done clear
  C)
   4 : 1                       done clear
  D)
   1 : 4 done clear
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• question_answer6)
  As we go to the higher altitudes the gravitational attraction of the earth
  A)
   increases                           done clear
  B)
   Decreases done clear
  C)
   Does not change             done clear
  D)
   First increase then decrease done clear
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• question_answer7)
  If the radius of the earth is 6400 km then weight of an object of mass 100 kg at height 6400 km from the surface of the earth is (g m the surface of the earth is\[\text{1}0\text{m}/{{\text{s}}^{\text{2}}}\])
  A)
   250 N    done clear
  B)
   1000 N done clear
  C)
   100 N                    done clear
  D)
   2500 N done clear
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• question_answer8)
  If the radius of the earth is 6400 km, the height above the surface of the earth, where the value of acceleration to gravity will be 1 % of the value on the surface of the earth
  A)
   6400 km              done clear
  B)
   64 km done clear
  C)
   57600 km       done clear
  D)
   2500 km done clear
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• question_answer9)
  If R is the radius of the earth, the height above the surface of the earth where the weight of the body is 36% less than its value on the surface of the earth
  A)
   \[\frac{4R}{5}\]                                                done clear
  B)
   \[\frac{R}{5}\] done clear
  C)
   \[\frac{R}{6}\]                                  done clear
  D)
   \[\frac{R}{4}\] done clear
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• question_answer10)
  The value of g is. with depth
  A)
   Increases                            done clear
  B)
   Decreases done clear
  C)
   Does not change             done clear
  D)
   increases or decreases done clear
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• question_answer11)
                  If the change in the value of g at a height above the surface of the earth is the same as at a depth\[x\]below it, and when both x and h are much smaller than the radius of the earth then
  A)
   \[x=h\]                                done clear
  B)
   \[x=2h\] done clear
  C)
   \[x=\frac{h}{2}\]                             done clear
  D)
   \[x=\frac{3h}{2}\] done clear
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• question_answer12)
  Ratio of g value at a depth \[{}^{R}/{}_{5}\]. to a depth \[{}^{R}/{}_{10}\] from the surface of the earth is
  A)
   \[\frac{5}{10}\]                                done clear
  B)
   \[\frac{2}{1}\] done clear
  C)
   \[\frac{8}{9}\]                   done clear
  D)
   \[\frac{9}{8}\] done clear
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