Differentiate between balanced and unbalanced forces.
Balanced forces: Net force is zero, constant velocity. Unbalanced forces: Net force is non-zero, acceleration occurs.
What is the difference between internal and external forces?
External forces: Act on the system from outside, can change the system's momentum. Internal forces: Act within the system, do not change the system's momentum.
Compare the effect of doubling the net force versus doubling the mass on an object's acceleration.
Doubling net force: Doubles acceleration. Doubling mass: Halves acceleration.
Compare the motion of an object with zero net external force vs. non-zero net external force.
Zero net force: Constant velocity (or at rest). Non-zero net force: Acceleration.
Compare the directions of net force and acceleration.
Net Force: Direction of the net force can be in any direction. Acceleration: Acceleration is always in the same direction as the net force.
What is the effect of an unbalanced force?
Causes the system to accelerate in the direction of the net force.
What is the effect of doubling the net force on an object?
The object's acceleration doubles, assuming mass remains constant.
What is the effect of doubling the mass of an object, with the same net force applied?
The object's acceleration is halved.
What happens when the net external force on a system is zero?
The system's center of mass maintains a constant velocity (or remains at rest).
What is the effect of friction on a moving object?
Friction opposes the motion, resulting in a net force that is reduced, and thus a smaller acceleration.
Define Newton's Second Law.
The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass: $\vec{a}_{sys} = \frac{\sum \vec{F}}{m_{sys}}$
What is 'net force'?
The vector sum of all forces acting on an object or system. It determines the acceleration of the object.
Define acceleration in the context of Newton's Second Law.
The rate of change of velocity of an object, directly proportional to the net force and inversely proportional to the mass.
What are unbalanced forces?
When the net force acting on a system is not zero, causing the system to accelerate in the direction of the net force.
Define 'net external force'.
The sum of all forces acting on a system from outside the system, determining if the velocity of the system's center of mass will change.
