Chang sees the following formula on a website about newton’s second law. a = sigma f over m. what does the symbol f in the formula indicate that chang needs to do? he needs to find the net force acting on the object in a direction. he needs to use only forces acting in the direction of motion. he needs to combine the horizontal and vertical forces. he needs to multiply the horizontal and vertical forces.

He needs to find the net force acting on the object in a direction.

Explanation:

The second law of motion gives the relationship between force, acceleration and mass of an object. Its mathematical expression is given  by :

F represents the net force acting on the object. So, Chang needs needs to find the net force acting on the object in a direction. Hence, the correct option is (a).                  

d is the answer i came up with