Test: Gravitation - SSC CGL MCQ

The universal gravitational constant, represented by 'G', is 6.67 × 10⁻¹¹N m²/kg². This constant is essential in Newton's Law of Gravitation, which quantifies the strength of the gravitational force between two point masses.

The value of acceleration due to gravity 'g' decreases with altitude from the Earth's surface. This decrease is a result of the inverse square law of gravitation, where the gravitational force weakens as the distance from the Earth's center increases.

The rotation of Earth affects gravity differently based on latitude. This effect is quantified by the adjusted acceleration due to gravity formula, where the gravitational acceleration is modified by the term \(R\omega^2 \cos^2 \lambda\), with λ representing the latitude. At the poles and the equator, this effect varies, showcasing the impact of Earth's rotation on gravity.

The key disparity between mass and weight lies in their characteristics. Mass is an intrinsic property of matter that remains constant regardless of location, while weight is the gravitational force acting on an object that varies depending on the location due to differences in gravity. This distinction is crucial in understanding how objects interact with the Earth's gravitational field.

When an object is in free fall, such as during a state of weightlessness, the weight of the object is effectively zero. This occurs because the object and the gravitational force are in balance, resulting in the sensation of weightlessness. Understanding this concept is vital in comprehending the dynamics of objects in free fall scenarios.

When a lift accelerates downward, the spring balance reads less than the true weight of the object. This phenomenon occurs due to the counteracting force of acceleration acting in the opposite direction to gravity. Understanding how weight is perceived in different scenarios within a lift is essential in grasping the principles of gravitational forces.

According to Kepler's Harmonic Law, the square of a planet's orbital period (T) is directly proportional to the cube of the semi-major axis (a) of its orbit. This law essentially describes the relationship between the time a planet takes to orbit the Sun and the average distance of the planet from the Sun. It signifies that as the size of a planet's orbit increases, the time it takes to complete one orbit also increases in a specific mathematical relationship, demonstrating the harmonious balance in planetary motion.

Mercury is the planet in our solar system that is closest to the Sun. It orbits the Sun at an average distance of about 36 million miles (58 million kilometers) and is known for its extreme temperature variations due to its proximity to the Sun.

Kepler's First Law of Planetary Motion states that all planets orbit the Sun in elliptical paths with the Sun at one of the two foci. This law describes the shape of planetary orbits, emphasizing that they are not perfect circles but rather elongated ovals known as ellipses. This insight revolutionized the understanding of celestial motion and laid the foundation for modern astronomy.

Geostationary satellites are primarily used for communication purposes. These satellites appear stationary relative to Earth, making them ideal for telecommunications, broadcasting, internet connectivity, and other communication services. By orbiting at the same rate as Earth's rotation, they maintain a fixed position in the sky, allowing for consistent communication coverage over specific regions on Earth.

Polar satellites orbit in a north-south direction, passing over Earth's polar regions, and are typically in a low Earth orbit. This orbital path allows them to cover the entire surface of the Earth over multiple orbits. Due to their close proximity to Earth, polar satellites are commonly used for tasks such as weather monitoring and environmental observation.

Escape velocity is the minimum speed required for an object to break free from Earth's gravitational pull and enter space without falling back.Satellites, understanding escape velocity is crucial for launching and maintaining satellites in orbit. By exceeding this velocity, a satellite can overcome Earth's gravitational force and remain in its intended orbit.

Gravitational Potential Energy represents the work done to bring a unit mass from infinity to a specific point in a gravitational field. This concept is essential in understanding the energy associated with gravitational interactions and the potential energy stored in objects within a gravitational field.

The weight experienced on the Moon is different from that on Earth primarily because the Moon has a weaker gravitational force compared to Earth. This weaker gravitational pull on the Moon's surface results in objects weighing approximately one-sixth of what they would on Earth. Understanding this gravitational difference is essential in comprehending the variations in weight experienced on different astronomical bodies.

Saturn is the planet in our solar system known for its prominent ring system, composed of countless icy particles ranging in size from tiny grains to large chunks. These rings make Saturn one of the most visually striking planets and have fascinated astronomers and space enthusiasts for centuries.