Tag: universe and space

Questions Related to universe and space

The mass of the moon is about $1.2$% of the mass of the earth. Compared to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. Is the same

  2. Is smaller

  3. Is greater

  4. Varies with its phase

Show answer
Correct Option: A
Explanation:

Answer is A.

By Newton's Third Law and Newton's Law of Universal gravitation, the gravitational force the Earth exerts on the Moon is exactly the same as the force the Moon exerts on the Earth. 
F (Earth) = F (Moon)
However, the tidal forces are not equal - the Moon exerts a greater tidal force because tidal forces result from a difference in force across the object. Because the Earth has a greater diameter, the difference in the lunar force across the Earth will be greater than the difference that the terrestrial force exerts across the lunar diameter.

When a fruit falls from a tree,

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. only the earth attracts the fruit

  2. both the earth and the fruit attract each other

  3. only the fruit attracts the earth

  4. they repel each other

Show answer
Correct Option: B
Explanation:

According to the law of physics, the earth attracts the apple and the apple attracts the earth with the same intensity of gravity ( according to 3rd law of dynamics). However the displacement of the two bodies is inversely to their respective masses. The earth attracts the apple i.e it falls on an apple in a billionth of a billionth of a millimeter which is impossible to see.

Thus when a fruit falls from a tree both the earth and the fruit attract each other.

The gravitational force is a

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. contact force

  2. action at a distance force

  3. non contact force

  4. both (B) and (C)

Show answer
Correct Option: D
Explanation:

Gravitational force is a action distance force because it can interact with an object even they are not in physical contact with each other, yet they are able to exert a push or a pull despite their physical operation. Hence gravitational force is a action at a distance force.

Gravitational force is also a non contact force because non contact force is a force which acts on an object without coming in physically contact with each other which is similar to a action at a distance force.

The weakest forces of interaction among all classified forces are

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. electrostatic forces

  2. gravitational forces

  3. weak nuclear forces

  4. electromagnetic forces

Show answer
Correct Option: B
Explanation:

Gravitational force is the weakest of all the forces because its coupling constant is small in value. Gravity cannot be felt in day to day life because of the huge universe surrounding earth. Electromagnetic force is the strongest of all  force as it deals with microscopic particles.

The gravitational force between two bodies is

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. repulsive at large distances

  2. attractive at all places

  3. attractive at short distances

  4. repulsive at short distances

Show answer
Correct Option: B
Explanation:

Gravitation is a natural phenomenon by which all things with mass are brought towards one another. It is an attractive force and behaves uniformly for all values of $r$ (distance between the two bodies).

On the surface of the earth, force of gravitational attraction between two masses kept at distance d apart is 6 Newtons. If these two masses are taken to the surface of the moon and kept at the same distance d, the force between them will be

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. 1N

  2. 36N

  3. $\frac { 1 }{ 6 } $N

  4. 6N

Show answer
Correct Option: D
Explanation:

Gravitational force by Newton's law must remain the same.


hence, $(D)$ is correct.

In SI unit gravitational unit of force is called 

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $Gf$

  2. $Kgf$

  3. $N$

  4. All

Show answer
Correct Option: B
Explanation:

in SI system, gravitational unit of force is called kilogram force.

$1 gf =$

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $980 dyne$

  2. $98 dyne$

  3. $9.8 dyne$

  4. $0.98 dyne$


Show answer
Correct Option: A
Explanation:

$1 gf = 1 g$ mass $\times$ acceleration due to gravity = $980 dyne$

$1 gf =$

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $250N$

  2. $980 dynes$

  3. $56 dynes$

  4. All

Show answer
Correct Option: B
Explanation:

A force required to produce an acceleration due to gravity of earth in a body of mass 1g,is called gram force. $\displaystyle 1gm=1g\times 980c{ m }/{ { s }^{ 2 } }$ = 980 dynes.

One kilogramme force is the force due to gravity on a mass of

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $1 g$

  2. $10 g$

  3. $100 g$

  4. $1000 g$

Show answer
Correct Option: D
Explanation:

One kilogramme force is the force due to gravity on a mass of $1 $kilogramme or $1000 g.$