PLEASE HELP... i cant figure it out

The density of a substance is 4.0 g/cm3. if a sample of the substance has a volume of 25 cm3 then what is the mass

Unpolarized light of intensity so passes through two sheets of polarizing material whose transmission axes make an angle of 60∘ with each other as shown in the figure. what is the intensity of the transmitted beam, st?

Due sun 06/09/2019 11: 59 pm skip navigation questions correct q 1 [1/1] correct q 2 [1/1] correct q 3 [1/1] untried q 4 (0/1) untried q 5 (0/1) untried q 6 (0/1) untried q 7 (0/1) untried q 8 (0/1) untried q 9 (0/1) untried q 10 (0/1) grade: 3/10 print version start of questions two cyclists, 42 miles apart, start riding toward each other at the same time. one cycles 2 times as fast as the other. if they meet 2 hours later, what is the speed (in mi/h) of the faster cyclist?