Question

A circular disc of diameter 4cm are punched out of a sheet of brass of mass 0.4g/cm^2. What is the mass of 500 such discs

Answer 1

Answer:

given: d = 4 cm => r = 2 cm, unit weight = 0.4g/cm²

to find mass of 500 discs

mass of 500 disc = mass of one disc × unit weight

mass of one disc m

=> area of one disc × unit weight

area A of one disc = πr²

=> 22/7 * 2*2 = 88/7 cm²

mass of one disc = 88/7*0.4 = 5 gm

therefore mass of 500 disc = 500×5 = 2500 gm

=> 2.5 kg