Day 1 Force A Vector Quantity Force a

Day 1: Force – A Vector Quantity � � � Force – a push or pull (in a certain direction) Forces are present in all mechanical systems Amount of push/pull (magnitude) is represented in units: a) Newtons (N) in the SI/metric system or; b) Pounds (Lbs) in the English system Force is a vector quantity because it has a magnitude and direction 5 N (fwd) A quantity that has a magnitude only (and no direction) is called a scalar Mass puck=0. 05 kg Makes sense right? Can’t have mass or temperature in a direction? ?

Day 1: Force – A Vector Quantity � � � The symbol for all vector quantities is a letter with a half arrow on top (ex. F). Ex: Malyka kicks the ball with a force of 5 N[East] notice magnitude with unit and direction in parentheses Therefore, F ball=5 N[East]

Day 1: Force – A Vector Quantity - the interaction of forces can be described by Newton’s 3 Laws of Motion: 1. Object in motion stays in motion or at rest stays at rest until external force acts on it (also known as inertia) When no outside forces act on an object, or all forces acting on it are equal, that object is in equilibrium(balance) 2. Acceleration of an object is proportional to the force applied to that object (F=ma). The greater the force the greater the acceleration and visa versa. 3. For every force applied there is an equal and opposite reaction force applied back.

FBD and System Diagram Practice Work Problems and Answers System Diagram FBD FN a) FG FAIR b) FG c) FF FN FG FA

Applying vectors: Net Force and Free Body Diagrams � � A Free Body Diagram(FBD) is used to represent the interaction of all forces in a system It is important to understand the different types of forces: Applied Symbol Description Normal Friction Gravity Air Resistance Tension Spring

Applying vectors: Net Force and Free Body Diagrams � � A Free Body Diagram(FBD) is used to represent the interaction of all forces in a system It is important to understand the types of forces that might be present: Type of Force Symbol Description Applied Fapp (Fa) An applied force is a force which is applied to an object by a person or another object. Normal Fnorm (Fn) The normal force is the support force exerted upon an object which is in contact with another stable object. Friction Ffrict (Ff) The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. Gravity Fgrav (Fg) The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. Air Resistance Fair The air resistance is a special type of frictional force which acts upon objects as they travel through the air. Tension Ftens (Ft) The tension force is the force which is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends. Spring Fspring (Fs) The spring force is the force exerted by a compressed or stretched spring upon any object which is attached to it.