Examples of net force in the following topics:

 The first condition of equilibrium is that the net force in all directions must be zero.
 That is, the net force and net torque on the object is zero in all directions.
 Note that if net $F$ is zero, then the net external force in any direction is zero.
 There are horizontal and vertical forces, but the net external force in any direction is zero.
 There are horizontal and vertical forces, but the net external force in any direction is zero.

 If a charged particle's velocity is parallel to the magnetic field, there is no net force and the particle moves in a straight line.
 There are many cases where a particle may experience no net force.
 Or there could be two or more forces on the particle that are balanced such that the net force is zero.
 If the net force on a particle is zero, then the acceleration is necessarily zero from Newton's second law: F=ma.
 If the acceleration is zero, any velocity the particle has will be maintained indefinitely (or until such time as the net force is no longer zero).

 In equilibrium, the net force and torque in any particular direction equal zero.
 so objects with constant velocity also have zero net external force.
 If no net force is applied to the object along the xaxis, it will continue to move along the xaxis at a constant velocity, with no acceleration .
 A moving car for which the net x and y force components are zero
 Determine the net force and the net torque for an object in equilibrium

 An object is said to be in equilibrium when there is no external net force acting on it.
 In both cases – static or dynamic – net external forces and torques are zero.
 A body is said to be in mechanical equilibrium when net external force is equal to zero and net external torque is also zero.
 Since there is no net force on the object, the object does not accelerate.
 In the second type, the object has a velocity, but since there are no net forces acting on it, the velocity remains constant.

 In this simple onedimensional example, without knowing the direction of the forces it is impossible to decide whether the net force is the result of adding the two force magnitudes or subtracting one from the other.
 When two forces act on a point particle, the resulting force or the resultant (also called the net force) can be determined by following the parallelogram rule of vector addition: the addition of two vectors represented by sides of a parallelogram gives an equivalent resultant vector which is equal in magnitude and direction to the transversal of the parallelogram.
 Ideally, these diagrams are drawn with the angles and relative magnitudes of the force vectors preserved so that graphical vector addition can be done to determine the net force.
 Forces are resolved and added together to determine their magnitudes and the net force.
 Determine how to derive net force from the parallelogram rule of vector addition

 2) if the object is a spherically symmetric shell (i.e., a hollow ball) then the net gravitational force on a body inside of it is zero.
 Since force is a vector quantity, the vector summation of all parts of the shell/sphere contribute to the net force, and this net force is the equivalent of one force measurement taken from the sphere's midpoint, or center of mass (COM).
 That is, a mass m within a spherically symmetric shell of mass M, will feel no net force (Statement 2 of Shell Theorem).
 The net gravitational force that a spherical shell of mass M exerts on a body outside of it, is the vector sum of the gravitational forces acted by each part of the shell on the outside object, which add up to a net force acting as if mass M is concentrated on a point at the center of the sphere (Statement 1 of Shell Theorem).
 The resulting net gravitational force acts as if mass M is concentrated on a point at the center of the sphere, which is the center of mass, or COM (Statement 1 of Shell Theorem).

 Net force affects the motion, postion and/or shape of objects (some important and commonly used forces are friction, drag and deformation).
 We know that a net force affects the motion, position and shape of an object.
 Another interesting force in everyday life is the force of drag on an object when it is moving in a fluid (either gas or liquid).
 Like friction, the force of drag is a force that resists motion.
 It omits the two vertical forces—the weight of the barge and the buoyant force of the water supporting it cancel and are not shown.

 Impulse, or change in momentum, equals the average net external force multiplied by the time this force acts.
 where F is the net force on the system, and Δt is the duration of the force.
 change in momentum equals the average net external force multiplied by the time this force acts.
 A force sustained over a long time produces more change in momentum than does the same force applied briefly.
 A graph of force versus time with time along the xaxis and force along the yaxis for an actual force and an equivalent effective force.

 Net external forces (that are nonzero) change the total momentum of the system, while internal forces do not.
 Newton's 2nd law, applied to an isolated system composed of particles, $\bf{F}_{tot} = \frac{d\bf{p}_{tot}}{dt} = 0$ indicates that the total momentum of the entire system $\bf{p}_{tot}$ should be constant in the absence of net external forces.
 Forces external to the system may change the total momentum when their sum is not 0, but internal forces, regardless of the nature of the forces, will not contribute to the change in the total momentum.
 There are mainly three kinds of forces: Gravity, normal force (between ice & pucks), and frictional forces during the collision between the pucks
 Since all the external forces cancel out with each other, there are no net external forces.

 Because of the third law, the forces between them are equal and opposite.
 This law holds regardless of the nature of the interparticle (or internal) force, no matter how complicated the force is between particles.
 Newton actually stated his second law of motion in terms of momentum: The net external force equals the change in momentum of a system divided by the time over which it changes.
 where $F_{net}$ is the net external force, Δp is the change in momentum, and Δt is the change in time.
 Because Δv/Δt=a, we get the familiar equation $F_{net} = ma$ when the mass of the system is constant.