In Chapter 2 we explored how several forces that act on a body can be subsumed into a net total force and torque. The body stays in rest, say at position $\mathbf q_0$, when the net force and torque vanish. Now we explore how the forces induce motion and how the position of the body evolves in time, $\mathbf q(t)$, when it is prepared with an initial condition $\mathbf q(t_0) = \mathbf q_0$ at the initial time $t_0$.

At the end of this chapter we will be able to discuss the likelihood for injuries in different types of accidents, be it men or cat or mice. Why do the cats go away unharmed in most cases when they fall from a balcony, while an old professor should definitely avoid such a fall. As a worked example we will discuss water rockets.

• 3.1 Motivation and outline: What is causing motion?
• 3.2 Time derivatives of vectors
• 3.3 Newton’s axioms and equations of motion (EOM)
• 3.4 Constants of motion (CM)
• 3.5 Worked example: Flight of an Earth-bound rocket
• 3.6 Problems
• 3.7 Further reading

The PDF file of the chapter is available here.