Rolling friction or rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc. is recovered when the pressure is removed.
Another cause of rolling resistance lies in the slippage between the wheel and the surface, which dissipates energy.
Section-1: General Science - Physics Question - 3
Mica sheets are used to provide structure for heating wire because:
It is a bad conductor of heat as well as electricity
It is a bad conductor of heat but a good conductor of electricity
it is a good electrical insulator at the same time as being a good thermal conductor
It is a good conductor of heat as well as electricity
Mica sheets are used to provide structure for heating wire in heating elements and can withstand up to 900 °C.
Sheet mica is used principally in the electronic and electrical industries. Its usefulness in these applications is derived from its unique electrical and thermal insulating properties and its mechanical properties, which allow it to be cut, punched, stamped, and machined to close tolerances.
Specifically, mica is unusual in that it is a good electrical insulator at the same time as being a good thermal conductor. The leading use of block mica is as an electrical insulator in electronic equipment
Compound (or catadioptric) telescopes, which use a combination of lenses and mirrors, offer compact tubes and relatively light weight; two popular designs are called Schmidt-Cassegrains and Maksutov-Cassegrains.