Explanation

Newton's law of universal gravitation states that every point mass attracts every other point mass by a force acting along the line intersecting both points.

This law applies to all objects in the universe, regardless of their size, shape, or composition.

Explanation

When a body is in unstable equilibrium, a slight tilt will cause its center of gravity (CG) to remain above the point of contact, making it prone to toppling over or falling.

This means that the CG is not directly over the point of support, but is still above it, creating a moment that tends to rotate the body further.

Key Points:

• A body is in stable equilibrium after slight tilt if its center of gravity remains above the point of contact.
• A body is in neutral equilibrium when its center of gravity remains at same height.

Explanation

This is a statement of Newton's second law of motion, which states that the force (F) required to accelerate an object is proportional to its mass (m).

Explanation

The first scientist who gave the concept of gravitation was Sir Isaac Newton.

He published his groundbreaking work, "Universal Law of Gravitation," in 1687.

It explained how gravity works and how it affects objects on Earth and in the universe.

Explanation

A tightrope walker carries a long pole to lower their center of gravity, making it easier to balance and maintain equilibrium.

By spreading their weight over a larger area (including the pole), they reduce the risk of toppling over.

Explanation

When a body is tilted slightly, if its center of gravity remains above the point of contact, it will tend to return to its original position, restoring equilibrium.

This is a characteristic of stable equilibrium.

Key Points:

• A body is in unstable equilibrium after slight tilt if its center of gravity remains above the point of contact.
• A body is in neutral equilibrium when its center of gravity remains at same height.

Explanation

The gravitational force between two masses is mutual; each mass exerts an equal and opposite force on the other,.

It aligns with Newton's 3rd law of motion: for every action, there is an equal and opposite reaction.

Explanation

To find the pressure, you need to divide the force (20 N) by the area (5 cm^2).

Since 1 cm^2 = 0.0001 m^2, the area in square meters is:

5 cm^2 x (0.0001 m^2/cm^2) = 0.0005 m^2

Now, you can calculate the pressure:

Pressure = Force / Area = 20 N / 0.0005 m^2 = 40,000 N/m^2

Since 1 N/m^2 = 1 Pascal (Pa), you can convert the pressure to N/cm^2:

40,000 N/m^2 x (1 m^2 / 100 cm^2) = 4 N/cm^2

Explanation

When a gas changes into a liquid, the molecules:

• Move closer together (their distance decreases)
• Lose kinetic energy (they slow down)

Explanation

If a spring stretches easily, it means that it requires less force to stretch it a certain distance.

This is indicative of a spring with a small spring constant (k).

The spring constant is a measure of a spring's stiffness.

A smaller value means the spring is less stiff and more easily deformed.