Pearson Science Year 7 Quiz!

An object that has kinetic energy must be in motion. Kinetic energy is the energy possessed by an object due to its motion. When an object is in motion, it has the ability to do work. If the object is at rest, it does not possess kinetic energy. Being elevated or upside down does not necessarily determine whether an object has kinetic energy or not.

Sound energy is the energy caused by an object's vibrations. When an object vibrates, it creates sound waves which travel through a medium, such as air or water. These vibrations transfer energy in the form of sound waves, which can then be detected by our ears. Sound energy is a type of kinetic energy, as it involves the movement of particles in the medium. It is distinct from other forms of energy, such as potential energy or thermal energy, as it specifically refers to the energy associated with vibrations and the transmission of sound waves.

Energy is defined as the ability to do work. In physics, work is defined as the transfer of energy from one object to another, or the transformation of energy from one form to another. Energy is not limited to just the ability to move, as it encompasses various forms such as mechanical, thermal, electrical, and chemical energy. 

The law of conservation of energy states that energy cannot be created or destroyed. This means that the total amount of energy in a closed system remains constant. While energy can change forms or be transferred from one object to another, it cannot be completely lost or gained. This principle is a fundamental concept in physics and is supported by numerous scientific experiments and observations.

Walking on the earth would make you feel the heaviest because the earth has the greatest gravitational pull that attracts objects towards its center. This gravitational force is responsible for giving objects weight. When you are standing on the earth's surface, you are being pulled towards its center, resulting in a feeling of heaviness. In contrast, the moon has a much weaker gravitational pull, so you would feel lighter while walking on its surface. Swimming in a pool or sitting in a satellite would not have the same gravitational force as walking on the earth, so you would not feel as heavy in those situations.

When electricity is turned on, it produces a magnetic force. This is because electric current flowing through a wire creates a magnetic field around it. The strength of the magnetic force depends on the amount of current flowing through the wire. This phenomenon is utilized in various electrical devices such as motors and generators, where the interaction between electricity and magnetism is used to produce mechanical energy or generate electricity.

A closed circuit is a complete electrical path that allows electricity to flow. It consists of a power source, conductors (such as wires), and a load (such as a light bulb or motor). When the circuit is closed, the electrical current can flow from the power source, through the conductors, to the load, and back to the power source, completing the circuit. If there is a break or gap in the circuit, it is considered open, and electricity cannot flow.

When the strings of a guitar vibrate more quickly, they produce a higher frequency of sound waves. Higher frequency sound waves are perceived as higher-pitched sounds. 

The term "field" is used to describe forces acting at a distance. In physics, a field is a physical quantity that exists throughout space and can exert a force on objects within its influence. Examples of fields include gravitational fields, electric fields, and magnetic fields. These fields can act on objects without direct contact, demonstrating the concept of forces acting at a distance.