I need help with this problem. It’s calculating net force.

The net force on the frog is  zero Newton.

Explanation:

Balance forces are 2 forces that is acting in opposite directions on an object, and equal in size. Anytime there is a balanced force on an object, the object stays still or continues moving continues to move at the same speed and in the same direction

In Figure , the forces exerted on the frog is equal in magnitude and opposite in direction.

Hence

The force , F1 = 200 N and F2 =  -200 N since it is acting in opposite direction

Now the net force =F1 + F2 =  200 - 200 = 0