Chapter 6: Kinetics of Point Masses
In the previous chapter we have discussed and developed a toolbox to analyse the kinematics of point masses, determining their motion, velocity and acceleration in various coordinate systems. In this chapter we extend our toolbox by determining the effect of forces on acceleration, thus analysing the kinetics of point masses.
The outline of this chapter is as follows. We first introduce Newton’s second law (Sec. 6.1) and use it to define mass (Sec. 6.2). We define force vectors and their properties governed by Newton’s third law (Sec. 6.3). Then we describe in detail the step-by-step procedure (Sec. 6.4) to determine and solve the equations of motion. The procedure starts from a sketch (Sec. 6.5) and choosing the coordinate system (Sec. 6.6). Then constraint equations are determined, free body diagrams are used to determine the resultant forces, and Newton’s second law is used to determine the equations of motion along each coordinate axis (Sec. 6.7-6.10), which are then solved (Sec. 6.11.1) to obtain the motion or forces (Sec. 6.11.2). Inertial reference frames are introduced (Sec. 6.12) and finally we discuss the properties of various forces (Sec. 6.13).