The material can transmit heat by energy transfer through collision of atoms. The elements that has a high ability of transmitting heat within their material are the metals. They are said to have high thermal conductivity. As the metal heats up, because the atoms are closely packed, they easily transfer heat through conduction. For example, copper is used in electrical wirings because it has a high thermal conductivity.
Thunderstorms happen when cold air sinks and hot air rises in rapid succession. There has to be an unstable body of hot air for a thunderstorm to happen. Cool air mingles with the hot air causing condensation (that means that raindrops form) This makes a cumulous cloud.
The moisture in the cloud is either positively charged or negatively charged. Negatively charged particles sink to the bottom of the cumulous cloud while positively charges particles rise. The positive and negative charges rub together and spark causing lightning.
Thunder is formed by the lightning, a bolt of lightning is hollow, and has no air inside it. When the lightning dissipates the air rushes to fill the space breaking the sound barrier in the process, this creates the boom.
Answer:
Some work input is lost to friction
Explanation:
The efficiency of a machine is defined as:
(1)
where
is the work output
is the work input
Due to the law of conservation of energy, the work output can never be larger than the work input (because energy cannot be created). Moreover, in real machines part of the work input is lost due to the presence of frictions: as a result, part of the energy in input is converted into thermal energy or other forms of energy, and so the work output is smaller than the work input, and so the ratio (1) becomes less than 1, and so the efficiency is less than 100%.
