(a) for a nonsmoker, with blood viscosity of 2.50 10-3 pa·s, normal blood flow requires a pressure difference of 8 mm hg between the two ends of a certain artery. if this person were to smoke regularly, his blood viscosity could increase to 2.80 10-3 pa·s (a 12% increase), and the diameter of his artery would constrict by 11%. what pressure difference between the ends of the artery would then be needed to maintain the same blood flow rate? mm of hg

13.6565mm of Hg

Explanation:

We only need to use the from Hagen poiseuille equation to be able to find the pressure change.  That is

Once the equation is defined, we clear based on the pressure and replace

Finally we have,

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.