For constant acceleration we will develop the equations that give us the velocity and position at any time. In particular we will study the motion under the influence of gravity close to the surface of the earth. | Chapter 2 Motion Along a Straight Line In this chapter we will study kinematics . how objects move along a straight line. The following parameters will be defined: Displacement Average velocity Average Speed Instantaneous velocity Average and instantaneous acceleration For constant acceleration we will develop the equations that give us the velocity and position at any time. In particular we will study the motion under the influence of gravity close to the surface of the earth. Finally we will study a graphical integration method that can be used to analyze the motion when the acceleration is not constant (2-1) Kinematics is the part of mechanics that describes the motion of physical objects. We say that an object moves when its position as determined by an observer changes with time. In this chapter we will study a restricted class of kinematics problems Motion will be along a straight line We will assume that the moving objects are “particles” . we restrict our discussion to . | Chapter 2 Motion Along a Straight Line In this chapter we will study kinematics . how objects move along a straight line. The following parameters will be defined: Displacement Average velocity Average Speed Instantaneous velocity Average and instantaneous acceleration For constant acceleration we will develop the equations that give us the velocity and position at any time. In particular we will study the motion under the influence of gravity close to the surface of the earth. Finally we will study a graphical integration method that can be used to analyze the motion when the acceleration is not constant (2-1) Kinematics is the part of mechanics that describes the motion of physical objects. We say that an object moves when its position as determined by an observer changes with time. In this chapter we will study a restricted class of kinematics problems Motion will be along a straight line We will assume that the moving objects are “particles” . we restrict our discussion to the motion of objects for which all the points move in the same way. The causes of the motion will not be investigated. This will be done later in the course. Consider an object moving along a straight line taken to be the x-axis. The object’s position at any time t is described by its coordinate x(t) defined with respect to the origin O. The coordinate x can be positive or negative depending whether the object is located on the positive or the negative part of the x-axis (2-2) Displacement. If an object moves from position x1 to position x2 , the change in position is described by the displacement For example if x1 = 5 m and x2 = 12 m then Δx = 12 – 5 = 7 m. The positive sign of Δx indicates that the motion is along the positive x-direction If instead the object moves from x1 = 5 m and x2 = 1 m then Δx = 1 – 5 = -4 m. The negative sign of Δx indicates that the motion is along the negative x-direction Displacement is a vector quantity that has both magnitude and direction. In this .
