Class 9 – Practice Level 2 – Gravitation Set 1 Leave a Comment / By anushka kumari / July 9, 2024 Class 9 - Practice Level 2 – Gravitation Set 1 Total questions: 25 1. Calculate the gravitational force between two 50 kg masses separated by a distance of 2 meters. $ \displaystyle \left( {\text{Use }G=6.67\times {{{10}}^{{-11}}}N{{m}^{2}}/k{{g}^{2}}} \right)$ Gravitational force: $ \displaystyle 8.34\times {{10}^{{-9}}}N$ Gravitational force: $ \displaystyle 4.17\times {{10}^{{-8}}}N$ Gravitational force: $ \displaystyle 1.67\times {{10}^{{-9}}}N$ Gravitational force: $ \displaystyle 1.67\times {{10}^{{-10}}}N$ None 2. If a person weighs 600 N on Earth, what would be their weight on Mars where the acceleration due to gravity is $ \displaystyle 3.7m/{{s}^{2}}$ ? Weight: 111 N Weight: 222 N Weight: 333 N Weight: 444 N None 3. Which force keeps a satellite in orbit around the Earth? Centripetal force Centrifugal force Frictional force Tension force None 4. An object is dropped from a height. Assuming no air resistance, what will be its velocity after 3 seconds? $ \displaystyle \left( {Use g=9.8m/{{s}^{2}}} \right)$ Velocity: 19.6 m/s Velocity: 29.4 m/s Velocity: 39.2 m/s Velocity: 49.0 m/s None 5. What is the gravitational potential energy of a 2 kg mass at a height of 5 meters above the ground? Potential energy: 49 J Potential energy: 98 J Potential energy: 147 J Potential energy: 196 J None 6. If the distance between two masses is reduced to one-third, how does the gravitational force between them change? It becomes nine times It becomes three times It becomes one-third It becomes one-ninth None 7. How does the value of g change with increasing altitude? It increases It decreases It remains constant It first increases then decreases None 8. What is the escape velocity from the surface of the Earth? 7.9 km/s 11.2 km/s 13.6 km/s 15.0 km/s None 9. According to Kepler's third law, the square of the orbital period of a planet is proportional to the cube of its: Average distance from the Sun Mass Radius Orbital speed None 10. What is the gravitational field strength at the surface of the Earth? $ \displaystyle 9.8N/kg$ $ \displaystyle 9.8m/{{s}^{2}}$ $ \displaystyle 6.67N/kg$ $ \displaystyle 6.67m/{{s}^{2}}$ None 11. Calculate the gravitational potential energy of a 10 kg object placed 10 meters above the ground. $ \displaystyle (\text{Use }g=9.8m/{{s}^{2}})$ 490 J 980 J 1960 J 3920 J None 12. A geostationary satellite orbits the Earth at an altitude of approximately: 36,000 km 42,000 km 48,000 km 54,000 km None 13. In a uniform gravitational field, the centre of mass of a body coincides with its: Centre of gravity Centre of buoyancy Centre of pressure Geometric center None 14. According to Newton's Law of Gravitation, if the mass of one object is tripled, the gravitational force between two objects will: Remain the same Triple Reduce to one-third Increase nine times None 15. If a person weighs 600 N on Earth, what would be their weight on Jupiter where the acceleration due to gravity is $ \displaystyle 24.8m/{{s}^{2}}$ ? 1500 N 1200 N 2400 N 3000 N None 16. Calculate the orbital speed of a satellite orbiting the Earth at an altitude of 200 km. $ \displaystyle \left( {\text{Radius of Earth R}=6400 km, g=9.8 m/{{s}^{2}}} \right)$ 7.9 km/s 8.4 km/s 9.2 km/s 10.1 km/s None 17. Which of the following statements correctly differentiates between mass and weight? Mass is a force; weight is a measure of inertia Mass varies with location; weight is constant Mass is constant; weight varies with location Mass is measured in newtons; weight is measured in kilograms None 18. The gravitational force between two masses is: Repulsive Attractive Both repulsive and attractive Neither repulsive nor attractive None 19. How far will an object fall in 4 seconds if it is dropped from rest? $ \displaystyle (Use g=9.8m/{{s}^{2}})$ 78.4 meters 39.2 meters 19.6 meters 9.8 meters None 20. Tides in the oceans are primarily caused by: The rotation of the Earth The gravitational pull of the Moon and the Sun The wind and weather patterns The Earth's magnetic field None 21. The components of the gravitational force that affect the orbits of planets are: Radial and tangential Radial and centrifugal Centrifugal and centripetal Tangential and centrifugal None 22. When an object is raised to a higher altitude, its gravitational potential energy: Decreases Increases Remains the same First decreases then increases None 23. If a person has a mass of 70 kg, what would be their weight on the Moon where $ \displaystyle g=1.6m/{{s}^{2}}$? 112 N 70 N 44.8 N 35 N None 24. The significance of the gravitational constant G in the Universal Law of Gravitation is that it: Determines the strength of the gravitational force Is the same as the acceleration due to gravity Varies with location Is only applicable to objects on Earth None 25. Calculate the orbital period of a satellite orbiting the Earth at an altitude where the orbital speed is 7.8 km/s. (Radius of Earth R=6400 km) 1.5 hours 2.0 hours 2.5 hours 3.0 hours None 1 out of 25 Time's up