How to measure net force based on diagram

[Blandpepper]

Could someone explain how to find the net force of an object based on a diagram. For example a 2 people walking with forces labeled weight force, reactant force, thrust and drag on one image all forces are balanced which I know the net force would be zero however on the second image thrust is larger than drag what would be the best way to calculate the net force (not a physical calculation using a formula as no sizes are given).

 

[PhanthomJay]

The net force acting on a system is the vector sum (resultant) force of all the forces acting on the system. It is often best to break up each of the forces into their vector x and y components and determine the net forces in each direction. Net forces produce accelerations in the direction of the net force. If there is a block on a rough level table and you push it with a force P in the positive x direction while a friction force f acts in the negative x direction , with no other forces acting in the x direction, then the net force is simply P - f , and if P is > f, the block will accelerate in the positive x direction. In the y direction, the block's weight is balanced by the normal force, so there is no acceleration in the y direction. See Newton's 1st and 2nd laws.

 

[sophiecentaur]

For example a 2 people walking with forces labeled weight force, reactant force, thrust and drag

I have just made a comment on another thread which could be relevant here. 'People walking' is not an easy situation in which to model forces with because people are highly non-ideal. A vast proportion of the forces which muscles produce are to do with the internal workings of the walker and have nothing to do with which way they are going.
The sorts of Physical situation that can be discussed with any hope of a useful outcome are those involving wheels (not motor tyres) smooth surfaces, low speeds in water and air and electrical circuits. We have to distinguish between theory and practice and this is why the best Physics Examination Questions are always clearly about situations that can be reduced to the very basics.
Sports performance, car crashes and suchlike need to be treated in a very different way from what basic Physics can do.

 

[ZapperZ]

Could someone explain how to find the net force of an object based on a diagram. For example a 2 people walking with forces labeled weight force, reactant force, thrust and drag on one image all forces are balanced which I know the net force would be zero however on the second image thrust is larger than drag what would be the best way to calculate the net force (not a physical calculation using a formula as no sizes are given).

You appear to be asking about a free-body diagram (FBD).

Before tackling on something more complex (2 people walking), let's back up a bit and see if you even understood the concept of a simpler FBD. Do you? Can you sketch all the forces on a simple mass sliding down an inclined plane?

There is no point in trying to tackle a complicated situation when it hasn't been established yet that you have understood a simpler situation.

Zz.