Chapter 4 Newton’s Laws

First Law An object at rest will remain at rest, until acted on by an outside forceAn object at rest will remain at rest, until acted on by an outside force An object in motion will remain at a constant speed, until acted on by an outside forceAn object in motion will remain at a constant speed, until acted on by an outside force

Second Law Acceleration can be measured using the formula:Acceleration can be measured using the formula: acc. = (net force) / mass. Force is measured in “Newtons” or N and mass is measured in kg The net force is the vector sum of all individual forces acting on the object.The net force is the vector sum of all individual forces acting on the object.

Third Law For every action, there is an equal and opposite reaction.For every action, there is an equal and opposite reaction.

Force Force is either an acting push or pull on an object.Force is either an acting push or pull on an object. Forces are vectors that have individual magnitudes and directions. The sum of these forces is the net force.Forces are vectors that have individual magnitudes and directions. The sum of these forces is the net force. Examples of force: force of gravity (Fg), an applied force (Fa), tension force (Ft),…Examples of force: force of gravity (Fg), an applied force (Fa), tension force (Ft),…

Free body diagram Free body diagrams are used to represent the forces acting on an object.Free body diagrams are used to represent the forces acting on an object. The object is represented as the origin of the diagram, with forces and their vectors represented as arrows.The object is represented as the origin of the diagram, with forces and their vectors represented as arrows. eg:eg:

Chapter 5

Equilibrium Problems These type of problems occur when an object is at rest or moving at a constant velocity.These type of problems occur when an object is at rest or moving at a constant velocity. Start by identifying all forces on a free-body diagram.Start by identifying all forces on a free-body diagram. To solve, use Newton’s Second LawTo solve, use Newton’s Second Law F=MAF=MA

Dynamics problems These type of problems occur when the object is accelerating.These type of problems occur when the object is accelerating. To start, sketch a picture to represent the motion of the object.To start, sketch a picture to represent the motion of the object. List out all of the known quantities as well as identify what you are trying to find.List out all of the known quantities as well as identify what you are trying to find. Identify all the forces on a free-body diagram.Identify all the forces on a free-body diagram. To solve, use Newton’s Second LawTo solve, use Newton’s Second Law F=MAF=MA

Objects in Contact Problems These type of problems occur when two or more objects interact.These type of problems occur when two or more objects interact. To start, sketch a picture representing the motion of the objects.To start, sketch a picture representing the motion of the objects. Identify all of the forces acting on each of the objects.Identify all of the forces acting on each of the objects. Identify all of the action/reaction pairs of forces in your system.Identify all of the action/reaction pairs of forces in your system. Draw a separate free-body diagram for each of the objects.Draw a separate free-body diagram for each of the objects. To solve, use Newton’s Second law to solve for each object individually. Next, use Newton’s Third Law to equate the magnitude of the action/reaction pairs. Then determine how the acceleration of the objects are related to each other.To solve, use Newton’s Second law to solve for each object individually. Next, use Newton’s Third Law to equate the magnitude of the action/reaction pairs. Then determine how the acceleration of the objects are related to each other.