(a) the volume flow rate in an artery supplying the brain is 3.4 x 10-6 m3/s. if the radius of the artery is 5.6 mm, determine the average blood speed.(b) find the average blood speed as a constriction in the artery if the constriction reduces the radius by a factor of 2. assume that the volume flow rate is the same as that in part (a).

a) speed = 3.45 × 10^-2 m/s

b) speed = 1.38 × 10^-1 m/s

Explanation: shown in the attachment

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.