)water at 20◦c flows at a rate of 0.020 m3/s through a 90◦ reducing elbow. the diameters at the entrance and exit are 0.050 m and 0.030 m, respectively, and the pressure at the exit is 105 pa. use macroscopic balance for momentum to compute the resultant components of the force [n] on the elbow neglecting gravitational and frictional effects.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

What are two different ways you could find the value of a? explain these methods.

How can you increase the strength of an electromagnet?