Force in Nature What is a Force A

What is a Force? • A push or a pull • Vector quantity •

In the Beginning… • Forces and how they interact between particles • http: //www.

Four Fundamental Forces 1. ) Gravitational Force • Force of attraction between all objects

2. ) Electromagnetic Force • Force caused by electric charges • Includes static electricity

3. ) Strong Nuclear Force • Holds protons and neutrons together in the nucleus

4. ) Weak Nuclear Force • Force between electrons and protons • Only noticeable

Everyday Forces Normal Force (FN) – a force perpendicular to the surfaces of objects

Friction (Ff) – force between objects in contact and parallel to contact surfaces -

Force of Gravity (Fg) – attraction between any objects that have mass Applied Force

Drawing Force Diagrams Free-Body Diagram (FBD) – drawing that includes only the objects being

Steps to Creating a FBD 1) Draw a box on an appropriate surface 2)

NOTE: The magnitude of the forces in opposite directions will be equal if the

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Force in Nature

What is a Force? • A push or a pull • Vector quantity • Measured in Newtons (N) • It can speed things up, slow them down, change direction, distort shapes by compressing and twisting etc.

In the Beginning… • Forces and how they interact between particles • http: //www. youtube. com/watch? v=p 5 QXZ 0__8 VU • How the big bang occurred ▫ http: //www. youtube. com/watch? v=uab. Ntl. Lf. Yy. U&feature=related

Four Fundamental Forces 1. ) Gravitational Force • Force of attraction between all objects in the universe • “action at a distance” force – objects do not need to touch • Only noticeable with large objects • Weakest force

2. ) Electromagnetic Force • Force caused by electric charges • Includes static electricity and magnetism • Attraction and repulsion based on charge

3. ) Strong Nuclear Force • Holds protons and neutrons together in the nucleus of the atom • Short range force (only significant when particles are close together)

4. ) Weak Nuclear Force • Force between electrons and protons • Only noticeable at extremely small distances

Everyday Forces Normal Force (FN) – a force perpendicular to the surfaces of objects in contact

Friction (Ff) – force between objects in contact and parallel to contact surfaces - Caused by attractive forces between particles of each object Tension (FT) – force exerted by ropes, strings or cables on objects. Can only be a pulling force

Force of Gravity (Fg) – attraction between any objects that have mass Applied Force (FA) – usually a push; any force that is applied by an external object that is not a rope, cable, etc.

Drawing Force Diagrams Free-Body Diagram (FBD) – drawing that includes only the objects being analyzed, arrows show forces acting on the object

Steps to Creating a FBD 1) Draw a box on an appropriate surface 2) Place a dot in the middle of the box ▫ All forces act outwards from the centre of mass (the middle) 3) Draw in all forces in the direction that they act

NOTE: The magnitude of the forces in opposite directions will be equal if the object is at rest!!!

Example of a Free Body Diagram

Example of System Diagram

Questions: • Pg 65 # 1, 2, 4, 5