Class 9 – Gravitation Numerical Set (Final Exam
Preparation)
25 Mixed Level Numerical Questions (■ = Advanced Level)
1. Calculate the gravitational force between two masses of 6 kg and 8 kg kept 2 m apart. (G = 6.67×10■¹¹
N·m²/kg²).
2. A ball is dropped from a height of 100 m. Find the time taken to reach the ground and its velocity just
before hitting the ground.
3. A stone is thrown vertically upward with a speed of 20 m/s. Find the maximum height reached and total
time of flight.
4. ■ A satellite orbits Earth at a height equal to the radius of Earth. If the radius is 6.4×10■ m and M =
6×10²■ kg, find its orbital speed.
5. A 5 kg object weighs 49 N on Earth. What will it weigh on the Moon if g_moon = 1.6 m/s²?
6. ■ Find the value of acceleration due to gravity on the surface of a planet whose mass is 5×10²■ kg
and radius is 4×10■ m.
7. An iron cube of side 0.1 m has a density of 7800 kg/m³. Find its mass.
8. ■ A cube of wood of density 600 kg/m³ floats on water. What fraction of its volume is above water?
9. A block of mass 200 g experiences an apparent loss of 40 g when immersed in water. Find its density.
10. ■ Two small spheres of equal mass attract each other with a force of 3×10■¹■ N when kept 1.5 m
apart. Find the mass of each sphere.
11. A metal block has a volume of 200 cm³ and mass 1.5 kg. Find its density.
12. A 10 kg body is dropped from a height of 80 m. Find the speed just before touching the ground (take g
= 9.8 m/s²).
13. ■ A satellite revolves around Earth with a period of 1.5 hours. Calculate its orbital radius. (Take G =
6.67×10■¹¹, M = 6×10²■ kg).
14. Find the pressure exerted by a 200 N force on an area of 0.01 m².
15. ■ A balloon of volume 0.3 m³ and mass 0.4 kg rises in air of density 1.29 kg/m³. Find its acceleration
upward (g = 9.8 m/s²).
16. A body weighs 100 N in air and 60 N when immersed in water. Find the buoyant force acting on the
body.
17. ■ Find g at a height equal to the radius of Earth. Take g = 9.8 m/s² at the surface.
18. A block of wood of density 800 kg/m³ floats in a liquid of density 1000 kg/m³. Find the fraction
submerged.
19. A sphere of radius 5 cm is completely immersed in water. Find the buoyant force acting on it. (Density
of water = 1000 kg/m³).
20. A 2 kg stone is dropped from a height of 20 m. Find the potential energy lost and kinetic energy
gained.
21. ■ Two planets have the same mass but radii in ratio 2:1. Find the ratio of acceleration due to gravity
on their surfaces.
22. A 50 N force acts on an area of 0.05 m². Find the pressure.
Preparation)
25 Mixed Level Numerical Questions (■ = Advanced Level)
1. Calculate the gravitational force between two masses of 6 kg and 8 kg kept 2 m apart. (G = 6.67×10■¹¹
N·m²/kg²).
2. A ball is dropped from a height of 100 m. Find the time taken to reach the ground and its velocity just
before hitting the ground.
3. A stone is thrown vertically upward with a speed of 20 m/s. Find the maximum height reached and total
time of flight.
4. ■ A satellite orbits Earth at a height equal to the radius of Earth. If the radius is 6.4×10■ m and M =
6×10²■ kg, find its orbital speed.
5. A 5 kg object weighs 49 N on Earth. What will it weigh on the Moon if g_moon = 1.6 m/s²?
6. ■ Find the value of acceleration due to gravity on the surface of a planet whose mass is 5×10²■ kg
and radius is 4×10■ m.
7. An iron cube of side 0.1 m has a density of 7800 kg/m³. Find its mass.
8. ■ A cube of wood of density 600 kg/m³ floats on water. What fraction of its volume is above water?
9. A block of mass 200 g experiences an apparent loss of 40 g when immersed in water. Find its density.
10. ■ Two small spheres of equal mass attract each other with a force of 3×10■¹■ N when kept 1.5 m
apart. Find the mass of each sphere.
11. A metal block has a volume of 200 cm³ and mass 1.5 kg. Find its density.
12. A 10 kg body is dropped from a height of 80 m. Find the speed just before touching the ground (take g
= 9.8 m/s²).
13. ■ A satellite revolves around Earth with a period of 1.5 hours. Calculate its orbital radius. (Take G =
6.67×10■¹¹, M = 6×10²■ kg).
14. Find the pressure exerted by a 200 N force on an area of 0.01 m².
15. ■ A balloon of volume 0.3 m³ and mass 0.4 kg rises in air of density 1.29 kg/m³. Find its acceleration
upward (g = 9.8 m/s²).
16. A body weighs 100 N in air and 60 N when immersed in water. Find the buoyant force acting on the
body.
17. ■ Find g at a height equal to the radius of Earth. Take g = 9.8 m/s² at the surface.
18. A block of wood of density 800 kg/m³ floats in a liquid of density 1000 kg/m³. Find the fraction
submerged.
19. A sphere of radius 5 cm is completely immersed in water. Find the buoyant force acting on it. (Density
of water = 1000 kg/m³).
20. A 2 kg stone is dropped from a height of 20 m. Find the potential energy lost and kinetic energy
gained.
21. ■ Two planets have the same mass but radii in ratio 2:1. Find the ratio of acceleration due to gravity
on their surfaces.
22. A 50 N force acts on an area of 0.05 m². Find the pressure.
