A net force is the overall force acting on an object, taking into account all of the individual forces acting on it in different directions.
Net force is calculated by adding together all of the forces acting on an object, taking into account their direction and magnitude. This can be done using vector addition or by using the equation Fnet = ma, where Fnet is the net force, m is the mass of the object, and a is the acceleration.
Calculating the net force on an object is important because it helps us understand the motion of the object. If the net force is zero, the object will remain at rest or continue moving at a constant velocity. If the net force is not zero, the object will accelerate in the direction of the net force.
Newton's First Law states that an object will remain at rest or in motion with constant velocity unless a net force acts upon it. Newton's Second Law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Newton's Third Law states that for every action, there is an equal and opposite reaction. The net force takes into account all of these laws and helps us understand the overall motion of an object.
The net force on the roof can be determined by identifying all of the individual forces acting on it, such as the weight of the roof, any external forces (such as wind or snow), and any internal forces (such as the support of the building). These forces can then be added together to calculate the net force on the roof.