Practice MCQ Questions and answers on Physics-GK

If the distance is doubled, the force of gravity is one-fourth as strong as before.

The term galaxy refers to a large collection of stars, dust, and gas clouds which are held together by gravitational attraction.The smallest galaxies may contain only a few hundred thousand stars, while the largest galaxies have thousands of billions of stars. The Milky Way galaxy contains our solar system.

Earth's gravity is 6 times moon's gravity. That means moon attracts an object with less force than earth. Hence a person can jump higher on moon than on earth.

The velocity required to place a vehicle in orbit around the moon is less than required to place it in orbit round the earth.

Weight is a measure of force that is equal to the gravitational pull on an object. Mass is independent of location, while weight depends on location.

A spacecraft leaving the surface of Earth, for example, needs to be going about 11 kilometers (7 miles) per second, or over 40,000 kilometers per hour (25,000 miles per hour), to enter orbit. Achieving escape velocity is one of the biggest challenges facing space travel.

The period of revolution of a geostationary satellite is 24 hours.

Johannes Kepler was a 16th century astronomer who established three laws which govern the motion of planets around the sun. These are known as Kepler's laws of planetary motion.

In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity.

The minimum velocity required for a rocket to overcome earth's gravity and travel into space is 11.2 km/sec.