Skip to main content

Gravitational force class 9 numerical problems

 Physics numerical :- chapter- Gravitational force



 Q.1.  What will be the weight of an object weighing 15 kgf on the moon? :-


 A) 12 N

 B) 15 N

 C) 25.83 N N

 D) 22.11 N

 ANSWER= C) 25.83 N

 Explanation:- To convert kgf to newton, it is multiplied by 9.8.

 Therefore,

 15kgf = 15×9.8

 =155.0N

 The weight of the object on the Moon is ⅙ times the weight of the object on the Earth.

 Therefore, the weight of a 15kgf object on the moon would be 155÷6 = 25.83 N.


 Q.2.  The value of g is 9.3 at a height of 100 m, then at what depth from the surface of the earth will the value of g become 9.3 m/s²?:-


 A) 200 m

 B) 100 m

 C) 400 m

 D) 900 m

 ANSWER= A) 200 m

 Explain:- The value of g at h height and g at d depth has the following relation:-

 d =2h

 so d=2×100

 =200 m


 Q.3.  What is the weight of 1 kg object? :-


 A) 98 N

 B) 1000 N

 C) 1 N

 D) 9.8 N

 ANSWER= D) 9.8 N

 Explain:-  Weight W = mg

 = 1×9.8

 = 9.8 N


 Q.4.  If the weight of an object on earth is m, then what will be the weight of this object on the moon?:-


 A) m/6

 B) m

 C) 6m

 D) m/3

 ANSWER= A) m/6

 Explain:-


 Q.5.  What will be the weight of a 15 kg object on the moon? (g=10 m/s²):-


 A) 15 N

 B) 30 N

 C) 20 N

 D) 25 N

 ANSWER= D) 25N

 Explain:-  Weight of 15 kg object on earth = 15×10

 = 150N

 Weight of the object on the moon = ⅙ of the weight of the object on the earth

 = 150 ×⅙

 = 25

 

 Q.6.  Two objects whose masses are 10kg and 20kg are placed at a distance of 100m from each other.  What will be the gravitational force between the two objects? :-


 A) 15.87× 10- 11 N

 B) 0.1334 × 10-11 N

 C) 23.5× 10-11 N

 D) 11.54 × 10-11 N

 ANSWER= B) 0.1334 × 10-11 N

 Explain:- F = G( m₁m₂)÷ r²

 ={ 6.67 ×10-¹¹ ×(10×20)}÷ (100)²

 = (6.67 ×10-¹¹)200÷ 10000

 = 13.34 × 10-¹¹ 100

 = 0.1334 ×10-¹¹ N

 

 Q.7.  The weight of a 2kg object on a planet is 18 Newtons.  What will be the value of g on that planet?


 A) 2  m/s²

 B) 18  m/s²

 C) 10  m/s²

 D) 9 m/s²

 ANSWER= D) 9 m/s²

 Explain:-  weight = mg

 18= 2 × g

 g= 18÷2

 = 9m/s²


 Q.8.  How much acceleration can 1 gram force(gf) produce on a 1g object?


 A) 9.8 m/s²

 B) 980 m/s²

 C) 4.9 m/s²

 D) 98 m/s²

 ANSWER= B) 980 m/s²

 Explain:-


 Q.9.  How much acceleration can 1 kilogram force(kgf) produce on a 1kg object?


 A) 9.8 m/s²

 B) 980 m/s²

 C) 4.9 m/s²

 D) 98 m/s²

 ANSWER= A) 9.8 m/s²

 Explain:-


 Q.10.  10 kgf force is equal to how many dynes?


 A) 980 × 10⁵

 B) 9.8 × 10⁵

 C) 98 × 10⁵

 D) 9 × 10⁵

 ANSWER= C) 98 × 10⁵

 Explain:-  10 kgf = 10×9.8 N

 = 98 N

 1 N = 10⁵ dyne

 98 N = 98 × 10⁵ dyne


 Q. 11. The distance between two objects of mass 2 kg and 5 kg is 0.4 m.  What will be the gravitational force between them?


 A) 33.7 × 10-¹¹ N

 B) 44.7 × 10-¹¹ N

 C) 416.8 × 10-¹¹ N

 D) 51.7 × 10-¹¹ N

 ANSWER= C) 416.8 × 10-¹¹ N

 Explain:- F = G( m₁m₂)÷ r²

 ={ 6.67 ×10-¹¹ ×(2 ×5)÷ (0.4)²}

 = 66.7 ×10-¹¹÷ 0.16

 = 416.8 × 10-¹¹


 Q.12.  The mass of an object on Earth is m.  What would be the mass of this object on the moon?  


 A) m

 B) m/6

 C) m/3

 D) 2m

 ANSWER= A) m

 Explain:- The value of weight changes but the value of mass remains the same everywhere.

Labels:

Comments

Post a Comment

Popular posts from this blog

Repeatedly asked MCQs questions on Venturimeter.

  1) Venturimeter is used to measure:- A) velocity of fluids. B) power C) pressure D) discharge of flow. Ans:- D) discharge of flow. 2) Small size Venturimeter is made of :- A) Brass or Bronze B) Cast iron C) Steel D) Nickel Ans:- A) Brass or Bronze 3) Large size Venturimeter is made of:- A) Cast iron B) Copper C) Nickel D) Brass Ans:- A) Cast iron 4) Angel of convergent cone of a Venturimeter is:- A) lesser than that of divergent cone. B) greater than that of divergent cone. C) equal to divergent cone. D) equal or less than that of divergent cone. Ans:- B) greater than that of divergent cone. 5) Venturimeters have:- A) low head loss, low coefficient of discharge and large size. B) low head loss, low coefficient of discharge and small size. C) high head loss, low coefficient of discharge and small size. D) low head loss, high coefficient of discharge and large size. Ans:- D) low head loss, high coefficient of discharge and large size. 6) The size of Venturimeter is expressed as 200...
Post a Comment
Read more

Best tricks to remember atomic mass number.

  Best trick to remember atomic weight number in Hindi  Here is a very good way to remember atomic mass number so that you can remember atomic mass number very easily   Atomic Mass Number :- The mass number of an atom is the sum total of the number of protons and the number of neutrons.  Z = p + n  The atomic mass number is expressed in amu(atomic mass unit) .   To prepare for various exams, you must read these posts of ours:-  biology gk set-1  V.V.I gk Question :- Reflection and Refraction of Light  pH value gk questions  Geography Set-1(100 Questions)  In this method you must remember the value of atomic number of elements. Here is how to calculate mass number up to 40.  This method fails when the mass number is more than 40.  Generally questions up to mass number 40 are asked in the examinations.  Mass numbers greater than that will have to be crammed or another method is adopted.  • How to easily remember th...
Post a Comment
Read more

Force and momentum numerical problems

 Physics numerical :- Force and Momentum  Q.1 .  A force of 12 N on an object produces an acceleration of 4 m/s.  How much force is needed to produce an acceleration of 10 m/s?  A) 30N  B) 12N  C) 10N  D) 20N  ANSWER= A ) 30N  Explain:-  F = ma  m = F/a  m = 12/4  m =3 kg  Therefore, force for an acceleration of 10 m/s² = ma  = 3×10  = 30N ans.  Q.2.  The momentum of an object is 20 kgm/s.  How much force is needed to stop it in 4 seconds :-  A) 4N  B) 12N  C) 10N  D) 5N  ANSWER= D) 5N  Explain:- From the formula of impulse,  force × time = change in momentum  Now, initial momentum = 20 kgm/s  Final momentum = 0 kgm/s (momentum also becomes zero when velocity is zero)  Change in momentum = 20 - 0  = 20 kgm/s  Therefore, F× 4=20  F = 20/4  = 5N ans.  Q.3.  An 80 g bullet is fired from a 20 kg gun with a velocit...
Post a Comment
Read more