Kinematics 2. Moving point: a moving point under studying 3. Three kinds of motion and their velocities and accelerations 1)Absolute motion: motion of the moving point relative to the SCS. Motion of 2)Relative motion: motion of the moving point relative to the MCS. particle For example, motions of a person in a running bus 3)Convected motion: motion of the MCs relative to the SCS. Motion of a For example, motion of a running care relative to the earth ground rigid body The velocity and acceleration of the moving point in its a bsolute motion are called absolute velocity va and absolute acceleration The velocity and acceleration of the moving point in its relative motion are called relative velocity vr and relative acceleration ar The velocity and acceleration of the convected point in its absolute motion are called convected velocity Vand convected acceleration a convected point: the point in the mcs coinciding with the moving point at any instant of time. Image that the moving point were fixed to the MCs and moved together with the MCs. Such a point in the Mcs is called convected point 77 3．Three kinds of motion and their velocities and accelerations 1) Absolute motion：motion of the moving point relative to the SCS. 2) Relative motion：motion of the moving point relative to the MCS. For example, motions of a person in a running bus 3) Convected motion：motion of the MCS relative to the SCS. For example, motion of a running care relative to the earth ground. The velocity and acceleration of the moving point in its absolute motion are called absolute velocity and absolute acceleration The velocity and acceleration of the moving point in its relative motion are called relative velocity and relative acceleration The velocity and acceleration of the convected point in its absolute motion are called convected velocity and convected acceleration aa ve ae vr ar va convected point: the point in the MCS coinciding with the moving point at any instant of time. Image that the moving point were fixed to the MCS and moved together with the MCS. Such a point in the MCS is called convected point. Motion of a particle Motion of a rigid body 2. Moving point：a moving point under studying