To determine the net force of the system, we need to consider the forces acting in opposite directions.
You have:
- The force exerted by the cue ball: 70 N to the left (this can be considered as positive).
- The force exerted by the four ball: 50 N to the right (and you are considering this as negative).
We can calculate the net force using the following equation:
\[ \text{Net Force} = \text{Force left} + \text{Force right} \]
Which, in this case, becomes:
\[ \text{Net Force} = 70 , \text{N} + (-50 , \text{N}) \] \[ \text{Net Force} = 70 , \text{N} - 50 , \text{N} \] \[ \text{Net Force} = 20 , \text{N} \]
The net force of the system is \( 20 , \text{N} \). Hence, the correct response is:
20 N.