Choice 'b' is one possible way to state
Newton's second law of motion.
The other choices are meaningless.
Answer:
A) object moves 20 N [West] or -20 N [East]
B) object moves 6 N [South] or -6 N [North]
C) object moves 90 N [West] or -90 N [East]
D) object does not move and is at rest*
*Rest means 0
Why:
A)both forces from north and south that are pushing against the object neutralize each other. Assume that north is positive and south is negative: 20 [N] + (-20) [S] = 0
On West and east, you can see that west has a greater force. Assume that west is negative and east is positive: 50 [E] + (-70) [W] = -20 [E]
Speed is scalar, meaning it's only going to be like 74 mph, doesn't matter which direction. Velocity is a vector, meaning it has direction. You can go -74mph when talking about velocity, not speed.
Answer:
Explanation:
Given
volume 
Suppose base is square with side L
height of crate is h
Volume 

Cost of top and bottom area 
Cost of Side area 
Total Cost 
Total Cost 
Differentiate C w.r.t Length




Dimensions are