Why is trying to maintain uniform wall thickness important when designing for an injection molded part? what are some considerations?

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Fluids at rest possess no flow energy. a)- true b)- false

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2