Final answer:
Net force is the sum of all forces acting on an object, dictating whether it will accelerate or remain at a constant velocity. The net force must be zero for no acceleration and a nonzero net force is required for acceleration, according to Newton's second law (Fnet = ma). Units for force problems are kilograms, meters, seconds, and meters per second squared for mass, distance, time, and acceleration respectively.
Step-by-step explanation:
The net force is the overall force acting on an object, which is the vector sum of all the forces. If forces are in the same direction, they are additive, and if they are in opposite directions, they are subtractive. According to Newton's second law of motion, if there is no acceleration, the net force must be zero, indicating that forces are balanced. If there is an acceleration, there must be a nonzero net force acting on the object. This acceleration is directly proportional to the net force and inversely proportional to the object's mass (Fnet = m*a). When an object moves at a constant speed or is not moving, it indicates that the net force is zero. One newton is the force it takes to change the velocity of a one-kilogram mass by one meter per second squared in one second. In solving problems where force is given in Newtons, the following units should be used: Mass in kilograms (kg), Distance in meters (m), Time in seconds (s), Speed in meters per second (m/s), and Acceleration in meters per second squared (m/s²).