Lecture 3 Notes

Force ( what does it do ? → act to change the velocity of something = > change speed , direction , or both ) no force acting on an object keep moving the same way changes the motion in the direction of the force ⊥ force is a vector quantity ⊥ force has defined direction ⊥ any acceleration that a force imparts to an object will be in the direction of the force Ñ acceleration ( due to the force ) Ms -2 F- = mam mass ( leg ) When does an object experience a force ? every object exerts a field . when you bring another object into that field a force will act = > interaction between the field with the new object when it enters a field ( region in space where something will exert an influence ) Coulombic forces when a charge enters the electric field associated with another charge or changed object All charges exert an electric field Field lines point FROM positive TO negative Field lines never cross Cover each other ) y straight out point outward / inward from / to point charges ( radially ) ⊥ single charge isolated in space field lines associated with the charge will point outward or inward , from or to that charge Field lines are drawn perpendicular to a charged surface > I ^ ? + + + + + + " " field " " " 㱺 " " " the field is & > < v v v v v v field gets stronger as you get closer to a point charge r > a L J v Force experienced by a charge in a field ( electric ) É= q É É electric field Erector for q = positive , force acts in direction of the field know direction of field = > know direction of force q= negative , force acts in direction opposite to the field field points positive → negative perpendicular to the surface accelerated in the direction of the force