PPT-Forces and Inertia

Force Interaction between two objects Mutual push or pull along the line Contact or over distance Measure it in Newton lb dyne 2015 Pearson Education Inc Forces and Inertia. The unit vectors 1 2 3 B e e e are fixed in the body and directed along a convenient set of axes pass ing through the mass center G The moments of inertia of the body about t hese axes are defined as 22 xx I y z dm 22 yy I x z dm 22 zz I x We consider the rotation of . rigid bodies. . A rigid body is an extended object (as opposed to a point object) in which the mass is distributed spatially.. Where should a force be applied to make it . Forces act on you all the time. . If . you surf, you can feel many forces pushing and pulling you in different directions. . Gravity . always pulls you down, towards planet Earth. . This . force can be balanced by the support of the surfboard acting upwards. . A chair will be placed in the middle of the floor. Teacher question: Are there any forces acting on this chair? . Invite . a student to gently push the chair a short distance across the floor. Ask the same teacher question . Conservation of rotational momentum. 1. Why does a wheel keep spinning. ?. Spinning ice skater . Video. . Why is a bicycle stable when it is moving, but falls over when it stops. ?. Why is it difficult to change the orientation of the axis of a spinning wheel?. Define . forces and different types of forces (push or pull). Measuring . forces in Newtons. Balanced . vs unbalanced forces. Inertia- . what is it and how does it apply to Newton’s first law of motion.. 1. st. Law of Motion. Inertia. An object will remain at rest or in constant motion unless acted upon by an unbalanced force. . “The Old Tablecloth Trick”. How does this comic relate to Inertia? . the forces between (among) individual particles (atoms, ions, molecules); they are weak relative to . intramolecular. forces (i.e. covalent and ionic bonds within a compound). Intermolecular forces are increasingly significant in this order:. Kris . Hauser. ECE 383 / ME 442. Spring 2015. Agenda. Basic elements of simulation. Derive the . standard form. of the dynamics of an articulated robot in joint space. Also works for humans, biological systems, non-actuated mechanical systems … . a = r. α. F = . mr. α. . Στ. = r . Σ. F . = . Σ. mr. 2. α. Moment of Inertia (. . I ) – sum of rotational inertia of an object. I = . Σ. mr. 2. . Στ. = I . α. Equation. Rotational Dynamics. Force. - a . push. or . pull . A . Force . 1. gives. . energy . to objects. 2. causes a. . change . in motion, such as:. . Starting. Speeding Up. Changing Direction. Stopping. Slowing Down. (Note: all of these are forms of . Dynamics I Forces & Newton’s First Law 4 Natural Forces Gravity : acts between all masses in the universe and has “infinite” range Electromagnetic (EM) Force : acts between electrically charged particles and “magnetically charged” poles The more mass an object has, the greater its inertia and the more force it takes to change its state of motion. . The amount of inertia an object has depends on its . mass. —which is roughly the . amount of material. . Scalars and vectors. . Types of forces. . Resultant of forces. . Equilibrium of particles. Scalar and Vectors. . Scalar - . a physical quantity that is completely described by a real number.