The valves of the heart and veins are similar in that they both: A.) Prevent blood from flowing too quickly.

B.) Are made of rigid cartilage.

C.) Prevent backflow of blood.

D.) Act as propellers to move blood forward.

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?

What are atoms of the same element with varying number of neutrons

Awater slide of length l has a vertical drop of h. abby's mass is m. an average friction force of magnitude f opposes her motion. she starts down the slide at initial speed vi. use work-energy ideas to develop an expression for her speed at the bottom of the slide. then evaluate your result using unit analysis and limiting case analysis. express your answer in terms of the variables h, m, l, vi, f and appropriate constants. vf v f