Class 9 - Practice Level 3 - Gravitation - Set 1

Total questions: 15

Two spherical objects have masses of 30 kg and 45 kg, and their centers are 0.5 meters apart. Calculate the gravitational force between them. $\displaystyle \left( {Use\text{ }G\text{ }=\text{ }6.67\times {{{10}}^{{-11}}}\,N{{m}^{2}}/k{{g}^{2}}} \right)$

Topic: Gravitational Force Between Two Spheres

$ \displaystyle {Gravitational\text{ }force:\text{ }4.00\times {{{10}}^{{-9}}}\,N}$

$\displaystyle {Gravitational\text{ }force:\text{ }3.60\times {{{10}}^{{-8}}}\,N}$

$ \displaystyle {Gravitational\text{ }force:\text{ }7.20\times {{{10}}^{{-8}}}\,N}$

$ \displaystyle {Gravitational\text{ }force:\text{ }9.00\times {{{10}}^{{-9}}}\,N}$

None

Calculate the gravitational potential energy of a system of two 20 kg masses separated by a distance of 2 meters.$\displaystyle \left( {Use\text{ }G\text{ }=\text{ }6.67\times {{{10}}^{{-11}}}\,N{{m}^{2}}/k{{g}^{2}}} \right)$

Topic: Gravitational Potential Energy in Two-Body System

$ \displaystyle {\text{Potential energy}:\text{ }-1.33\times {{{10}}^{{-8}}}\,J}$

$ \displaystyle {\text{Potential energy}:\text{ }-1.33\times {{{10}}^{{-9}}}\,J}$

$ \displaystyle {\text{Potential energy}:\text{ }-2.67\times {{{10}}^{{-8}}}\,J}$

$ \displaystyle {\text{Potential energy}:\text{ }-2.67\times {{{10}}^{{-9}}}\,J}$

None

Calculate the orbital speed of a satellite orbiting the Earth at an altitude of 800 km. $ \displaystyle \left( {Radius\text{ }of\text{ }Earth\text{ }R\text{ }=\text{ }6400\,km,\text{ }g\text{ }=\text{ }9.8\,m/{{s}^{2}}} \right)$

Topic: Orbital Speed Calculation

Orbital speed: 7.5 km/s

Orbital speed: 7.8 km/s

Orbital speed: 8.0 km/s

Orbital speed: 8.3 km/s

None

An object is dropped from a height of 80 meters. Assuming no air resistance, calculate the time taken to reach the ground.$ \displaystyle \left( {Use\text{ }g\text{ }=\text{ }9.8\,m/{{s}^{2}}} \right)$

Topic: Free Fall from Height Calculation

Time: 3.5 s

Time: 4.0 s

Time: 4.5 s

Time: 5.0 s

None

Calculate the gravitational field strength at a distance of 3000 km from the Earth's surface. $ \displaystyle \left( {Radius\text{ }of\text{ }Earth\text{ }R\text{ }=\text{ }6400\,km,\text{ }g\text{ }=\text{ }9.8\,m/{{s}^{2}}} \right)$

Topic: Gravitational Field Strength Calculation

Field strength: 4.0 N/kg

Field strength: 5.0 N/kg

Field strength: 6.0 N/kg

Field strength: 7.0 N/kg

None

Calculate the energy required to move a 10 kg mass from the Earth's surface to an altitude of 200 km. $ \displaystyle \left( {Radius\text{ }of\text{ }Earth\text{ }R\text{ }=\text{ }6400\,km,\text{ }g=9.8\,m/{{s}^{2}}} \right)$

Topic: Energy Required to Move Mass

Energy: 588 J

Energy: 548 J

Energy: 612 J

Energy: 408 J

None

If the mass of one object is tripled and the distance between two objects is halved, how does the gravitational force between them change?

Topic: Gravitational Force and Masses

It becomes 6 times

It becomes 12 times

It becomes 24 times

It becomes 36 times

None

Calculate the work done in lifting a 5 kg object to a height of 10 meters. $ \displaystyle \left( {Use\text{ }g\text{ }=\text{ }9.8\,m/{{s}^{2}}} \right)$

Topic: Work Done Against Gravity

Work done: 245 J

Work done: 450 J

Work done: 490 J

Work done: 980 J

None

A planet orbits the Sun at an average distance of 1 AU (astronomical unit). If another planet orbits at 4 AU, what is the ratio of their orbital periods?

Topic: Kepler's Third Law

Ratio: 2:1

Ratio: 4:1

Ratio: 8:1

Ratio: 16:1

None

10.

Calculate the gravitational potential energy of a 2 kg mass at a height of 50 meters above the ground.$ \displaystyle \left( {Use\text{ }g=9.8\,m/{{s}^{2}}} \right)$

Topic: Gravitational Potential Energy at Height

Potential energy: 490 J

Potential energy: 780 J

Potential energy: 980 J

Potential energy: 1960 J

None

11.

Calculate the net gravitational force on a 5 kg mass placed at the midpoint between two 10 kg masses separated by 1 meter.$ \displaystyle \left( {Use\text{ }G\text{ }=\text{ }6.67\times {{{10}}^{{-11}}}\,N{{m}^{2}}/k{{g}^{2}}} \right)$

Topic: Gravitational Potential Energy in Two-Body System

Net force: 10 N

Net force: 5 N

Net force: 50 N

Net force: 0 N

None

12.

Calculate the escape velocity from the surface of the Moon where the radius of the Moon is $ \displaystyle 1.74\times {{10}^{6}}\,m\text{ }and\text{ }g\text{ }=\text{ }1.6\,m/{{s}^{2}}$

Topic: Escape Velocity from Moon

Escape velocity: 1.2 km/s

Escape velocity: 1.6 km/s

Escape velocity: 2.4 km/s

Escape velocity: 3.2 km/s

None

13.

Using Kepler’s third law, determine the orbital period of a planet that is 5 AU away from the Sun if Earth's orbital period is 1 year.

Topic: Kepler's Laws Application

Orbital period: 5 years

Orbital period: 8 years

Orbital period: 11 years

Orbital period: 25 years

None

14.

If the distance between two masses is increased by a factor of 3, how does the gravitational force between them change?

Topic: Gravitational Force and Varying Distances

It becomes one-third

It becomes one-ninth

It becomes one-twentieth

It becomes one-thirtieth

None

15.

Newton’s law of gravitation applies to

Topic: Newton's Law of Gravitation

Solar system

Small bodies only

Large bodies only

All bodies irrespective of their size

None

1 out of 15

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Class 9 - Practice Level 3 - Gravitation - Set 1

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