A transverse pulse of frequency 9Hz travels 4.5m in 0.6s. Calculate the wavelength of the pulse

The melting point of a substance is equivalent to

A machine whose efficiency is 75% is used to lift a load of 1000N. Caalculate the effort put in to the machine if it has a velocity ratio of 4

A small amount of air is introduced into the vacuum above the mercury in a mercury barometer tube. The mercury level goes down because air molecules