3 kids are pushing on a cart 2 are pushing north at 50 N each. The 3rd is pushing South at -90 N. The net force is _N?

Explanation:

When two forces act in the same direction , they add up and when they act in opposite direction , they subtract .

2 forces each of 50 N act in same direction , so they will add up to give resultant force of 100 N . Now third force acts in opposite direction so 100 N and - 90 N will subtract to give total resultant force .

Resultant force = 100 - ( - 90 ) = 190 N

So net force or resultant force = 190 N .

the independent variable, or the one that is intentionally manipulated is the speed.