Final answer:
The magnitude of the resultant force is calculated by subtracting the smaller force from the larger force if they are in opposite directions, yielding a resultant force of 115 N in this scenario. Newton's second law, F = ma, allows us to calculate the acceleration of the system if the mass is known.
Step-by-step explanation:
To calculate the magnitude of the resultant force when two forces are applied on an object, we can simply subtract the smaller force from the larger force if they are in opposite directions. In this case, we have a 120 N force and a 5 N force applied in opposite directions. Therefore, the magnitude of the resultant force can be calculated by subtracting 5 N from 120 N, yielding 115 N.
Using Newton's second law, F = ma, where F is the force applied, m is the mass, and a is the acceleration, we can then calculate the acceleration if we know the mass of the object. For example, if a total mass of the system (two figure skaters) is 90 kg, and the net force applied is 115 N, the acceleration would be a = F/m, which equals 1.28 m/s2.