The roll size of a roll crusher was 30.5 cm × 90.1 cm. Gypsum rock (S.G. = 2.7, bulk density = 1.7 t/m 3) is to be crushed. Determine. 1. the set in order to crush at the rate of 12 t/h and 10 rpm speed of the rolls, 2. the ratio between capacity and peripheral speed if the set was 2.5 cm, 3. the nip angle when the crusher feed size is 10 cm,