The sum of all forces that act upon an object Reaction force
Net force
Unbalanced force
Balanced force

Think of each force as a push or pull on the object. For example, the force of gravity pulls down on an object, while the ground pushes back up to prevent the object from falling through the ground. This force pushing back up is known as the normal force.

1.4

2.3

step-by-step explanation:

the formula for the constant of variation is

y= kx

divide each side by x

y/x =kx/x

y/x =k

we know a and y

1.   y/x = k

4/1 =4

check the other values to make sure they are the same

8/2 = 4   12/3 =4   and 16/4 =4  

the constant of variation is 4

2.   y/x = k

3/1 =3

check the other values to make sure they are the same

6/2 = 3   9/3 =3   and 12/4 =3  

the constant of variation is 3