Balancing forces

When forces of equal size and in opposite directions act on an object, the forces are described as balanced. Objects without balanced forces will therefore have a resultant (net) force.

Key Concepts

Forces can act in 3-dimensions, but due to the limitations of computer/mobile screens, let's consider forces in 1 and 2-dimensions.

On the Earth:

weight acts vertically down
air creates drag

In space:

often negligible gravitational forces
no air to worry about

Essentials

Newton's First Law states that an object will remain at rest or at constant velocity unless acted upon by a resultant force.

Using astronauts, we can see that a body will stay at rest or continue with constant velocity if the forces are balanced.

Summary

If the force vectors acting on a body add up to zero then we say they are balanced. To determine if this is the case:

either join all vectors nose to tail and see if they form a closed shape
or resolve the forces into two perpendicular directions (e.g. vertically and horizontally) and see if they cancel out in each