1. What is gravity and the value of acceleration due to gravity on the surface of the earth ?

Gravity is the force of attraction between any two objects in the universe. The acceleration due to gravity is denoted by 'g' and has a value of approximately 9.8 m/s² on the surface of the earth.

2. What is the Universal Law of Gravitation?

The Universal Law of Gravitation states that the force of gravitational attraction between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

3. Calculate the gravitational force between two objects of masses 5 kg and 10 kg separated by a distance of 2 meters, using the universal law of gravitation.

Using the formula F = G * (m1 * m2) / d², where G = 6.673 x 10^-11 N m² / kg², m1 = 5 kg, m2 = 10 kg, and d = 2 meters, we get:

F = 6.673 x 10^-11 * (5 * 10) / (2²)

= 8.34 x 10^-10 N

4. What is free fall?

Free fall is the motion of an object falling under the influence of gravity alone.

5. What Is there a difference between mass and weight?

Mass is a measure of the amount of matter in an object, while weight is the measure of the gravitational force acting on an object. The SI unit of weight is the Newton (N).

6. What is the weight of an object of mass 50 kg on the surface of the earth? (Given: acceleration due to gravity on earth = 9.8 m/s²)

Weight of an object is given by the formula W = m * g, where m = 50 kg and g = 9.8 m/s². Therefore,

W = 50 * 9.8

= 490 N

Therefore, the weight of the object is 490 N on the surface of the earth.

7. What is the force that keeps objects in circular motion?

The force that keeps objects in circular motion is known as centripetal force.

8. What is the centripetal force acting on the moon to keep it in its orbit around the earth?

The centripetal force acting on the moon to keep it in its orbit around the earth is provided by the gravitational force of the earth on the moon.

9. Does the weight of an object change from place to place?

Yes, the weight of an object changes from place to place due to differences in gravitational acceleration.

10. What is the force of gravity on an object of mass m situated on or near the earth's surface?

The force of gravity on an object of mass m situated on or near the earth's surface is given by GMm/R², where G is the universal gravitational constant, M is the mass of the earth, and R is the distance between the object and the center of the earth.

11. What is the universal gravitational constant?

The universal gravitational constant (G) is a constant value used to calculate the force of gravity between any two objects in the universe. Its value is approximately 6.673 x 10^-11 N m²/kg².

12. Is the force of gravity a long-range force?

Yes, the force of gravity is a long-range force, as it acts over large distances between objects.

13. What is a fluid, and how does it exert pressure on its container?

A fluid is a state of matter that can flow, and all liquids and gases are fluids. As fluids have weight, they exert pressure on the base and walls of the container in which they are kept.

14. What is buoyancy, and how is it related to the volume and density of an object?

Buoyancy is the upward force experienced by an object immersed in a fluid. The magnitude of the buoyant force depends on the volume of the object immersed in the fluid and the density of the fluid.

15. What is Archimedes’ principle, and how is it related to the buoyant force?

Archimedes’ principle states that an object immersed fully or partially in a fluid experiences an upward force that is equal to the weight of the fluid displaced by it. This principle is directly related to the buoyant force experienced by an object in a fluid.

16. What are some practical applications of Archimedes’ principle?

Archimedes’ principle has many practical applications, such as in the design of ships, submarines, lactometers, and hydrometers.

17. What is density, and how is it measured?

Density is the mass of a substance per unit volume, and it is typically measured in kilograms per cubic meter (kg/m³). However, it can also be measured in grams per cubic centimeter (g/cm³), where 1 g/cm³ is equivalent to 1000 kg/m³.

18. How does an object's density relate to its ability to float or sink in a fluid?

If the density of an object is less than the density of the fluid in which it is immersed, the object will float on the surface of the fluid. However, if the density of the object is greater than the density of the fluid, the object will sink in the fluid.