Explanation

A burning candle is an example of all three states of matter:

• Solid: The wax is in a solid state.
• Liquid: The melted wax is in a liquid state.
• Gas: The vaporized wax and combustion products are in a gaseous state.

Explanation

In a solid, the particles (atoms, molecules, or ions) are closely packed and vibrate in place, holding their position in the crystal lattice.

This vibration is due to thermal energy, and the particles oscillate around their fixed positions.

Key Points:

• In a gas, particles are widely spaced and move freely.
• In a liquid, particles are close together but move past each other.

Explanation

The velocity of a satellite is independent of its mass.

According to Kepler's laws, velocity is determined by the orbit's semi-major axis and the central body's gravitational constant (G), not by the satellite's mass.

Explanation

The critical velocity (vc) is the minimum velocity an object must have to orbit the Earth without falling to the ground.

It is given by the formula:

vc = √(gR)

where:

• g is the acceleration due to gravity (approximately 9.8 m/s²)
• R is the radius of the Earth (approximately 6,371 kilometers)

Explanation

Rockets are used to put satellites into orbit around the Earth.

Rockets provide the necessary thrust and velocity to overcome the Earth's gravitational pull and reach the desired altitude and orbit.

Explanation

A communication satellite in a geostationary orbit completes one revolution around the Earth in 24 hours.

This is the same amount of time it takes the Earth to rotate once on its axis.

Explanation

The mass of Earth is approximately 6.0 x 10^24 kilograms.

This is a widely accepted scientific value, based on various measurements and calculations, including:

• Gravity measurements
• Satellite orbits
• Seismological data
• Planetary formation models

Explanation

• Your weight, as measured on Earth, will be decreased if you move to a planet or moon with a weaker gravitational field.
• Weight is the force exerted on an object by gravity.
• It depends on both the mass of the object and the strength of the gravitational field.

Explanation

A spring balance is a device used to measure the weight of an object.

It consists of a spring that is stretched or compressed by the weight of the object, and a pointer or dial that indicates the weight.

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.