Tag: universe and space

Quizzes (13) Questions (114)

Questions Related to universe and space

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity
State whether true or false.
Gravitational forces can also be repulsive like that of electrostatic forces.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gravitational force, $F=\cfrac { G{ M } _{ 1 }{ M } _{ 2 } }{ { R }^{ 2 } } $

Now the mass of the objects can not be opposite (i.e., mass cannot be negative), thus, the nature of the force cannot be repulsive like that of electrostatic force.

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

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

  1. is the same

  2. is smaller

  3. is greater

  4. Varies with its plane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The gravitation force of attraction between two bodies is given by, $F=-\dfrac{Gm _1m _2}{r^2}$ where $G=$ gravitational constant, $m _1,m _2$  be the masses of bodies and $r$ be the distance between them.

As the force depends on the product of masses and distance between them, so same force will exert on each other.

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

If E, M, J and G, respectively, denote energy, mass, angular momentum, and gravitational constant, then $EJ^2 / M^5G^2$ has the dimensions of

  1. Time

  2. Angle

  3. Mass

  4. Length
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$E=ML^2T^{-2}\ M+ML^0T^0\ G=M^{-1}L^3T^{-2}\ J=ML^2T^{-1}$

$EJ^2/M^5G^2=Ml^2T^{-2}\times M^2L^2T^{-1}$
$=M^5\times M^{-2}\times L^{-6}T^{-4}\ =M^0L^0T^0$

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

Choose the correct statement:

  1. The dimensional formula for $G$ is ${M}^{-1}{L}^{3}{T}^{-2}$
  2. $G$ is independent of medium
  3. $F=G\cfrac{{m} _{1}{m} _{2}}{{r}^{2}}$

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The dimensional formula for G is M^-1 L^3 T^-2, G is independent of the medium, and the formula F = G * m1 * m2 / r^2 is correct. All statements are true.

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

The force of attraction between two unit point masses separated by a unit distance is called

  1. Gravitational potential

  2. Acceleration due to gravity.

  3. Gravitational field

  4. Universal gravitational constant.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Universal gravitational constant is the force of attraction between two bodies of unit mass and at a unit distance from each other.

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

In the relation F= $\dfrac{G M m}{r^{2}}$, the quantity G

  1. depends on the value of g at the place of observation.

  2. is used only when the earth is one of the two masses.

  3. is greatest at the surface of the earth.

  4. is universal constant in nature.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

G is the universal gravitational constant which remains constant irrespective of the place and time. G is the force of attraction between two bodies of unit mass and unit distance apart.

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

A body of mass $5\ kg$ is cut into two parts of masses (a) $\dfrac {m}{4}; \dfrac {3m}{4}$ (b) $\dfrac {m}{7}; \dfrac {5m}{7}$ (c) $\dfrac {m}{2}; \dfrac {m}{2}$ (d) $\dfrac {m}{5}; \dfrac {4m}{5}$. When these two pieces are kept apart by certain distance; In which case the gravitational force acting is maximum?

  1. In case a

  2. In case C

  3. In case d

  4. In case b
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gravitation force between two masses is given by $F=\cfrac { G{ m } _{ 1 }{ m } _{ 2 } }{ { r }^{ 2 } } $

In case I:${ F } _{ 1 }=\cfrac { G\cfrac { m }{ 4 } .\cfrac { 3m }{ 4 }  }{ { r }^{ 2 } } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } \times \cfrac { 1 }{ 16 } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } \times 0.0625$
In case II: ${ F } _{ 2 }=\cfrac { G\cfrac { m }{ 7 } .\cfrac { 5m }{ 7 }  }{ { r }^{ 2 } } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } \times \cfrac { 5 }{ 7 } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } \times 0.714$
In case III: ${ F } _{ 3 }=\cfrac { G\cfrac { m }{ 2 } .\cfrac { m }{ 2 }  }{ { r }^{ 2 } } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } .\cfrac { 1 }{ 4 } =\cfrac { G{ m }^{ 2 } }{ { r }^{ 2 } } \times 0.25$
${ F } _{ 2 }$ is maximum.

Multiple choice social science universe and space the big bang and the early development of the universe origin of universe evolution of the universe

When the flow parameters of any given instant remain same at every point, then flow is said to be

  1. laminar

  2. steady state

  3. turbulent

  4. quasistatic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the flow parameters (like pressure, velocity etc) doesn't change w.r.t time i.e remains constant through out the time period, then this state is called as STEADY STATE.

Multiple choice social science universe and space the big bang and the early development of the universe origin of universe evolution of the universe

Universe is:

  1. a dialect between two people

  2. the study of light propagation between Sun and the Earth

  3. the vast surrounding space which includes everything that exists from the Earth to the most distant parts of space that one can possibly see

  4. the solar system
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The universe is the vast surrounding space which includes everything that exists from the Earth to the most distant parts of space that one can possibly see.