Questions

Deleted files are not permanently removed from the hard drive or the computers memory. Before they are permanently removed from the system they are stored in Recycle Bin. Recycle Bin is a folder or directory where deleted items are temporarily stored. It is also called as trash.

In the middle of the 6th centuryB.C, a powerful empire was established in Iran this empire which lasted over two centuries is known as the Achaemenid Empire. The founder of this Empire was Cyrus with his capital at pasargadae. In 539 B.C, cyrus defeated the Babylonians and extended his empire over a vast territory up to Asia Miner. His successor was Darius I (522-486 B.C).

A Contact force is a force applied to a body by another body that is in contact with it. Contact force acts on a point of direct contact between the two objects. This force can either be continuous as a continuous force or can be momentary in the form of an impulse. Contact force is governed by Newton’s Laws.

Examples :: Contact force is responsible for most of the interactions we experience in the daily life.

1. Writing your name with a pen, pushing a car up a hill, lifting an object, etc...

2. Kicking a ball, hammering a nail, etc...

are some of the everyday examples where contact forces are at work.

In the first case, the force is continuously applied by the person on the car or pen or an object while in the second case the force is delivered in a short impulse.

Contact forces are often decomposed into orthogonal components

one perpendicular to the surface in contact called the normal force, and

one parallel to the surface in contact, called the friction force.

The world's fastest elevator that can operate at a record speed of 1,260 meters per minute is set to be installed in a skyscraper complex in China. The elevator has various safety features including brake equipment that uses materials with high heat resistance. Apart from this, the elevator can absorb vibration during the high-speed operation to make the ride comfortable.

Rust forms when oxygen reacts with chemicals in rocks, and that is often the case with many other elements in general. Like a copper nail being exposed to the air will rust.

Atoms are composed of Electrons, protons and Neutrons. Protons and Neutrons together called as Nuclei.

Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years. There are 9 water soluble vitamins.