Paper 4, Section I, 3A

Dynamics and Relativity
Part IA, 2018

(a) Define an inertial frame.

(b) Specify three different types of Galilean transformation on inertial frames whose space coordinates are x\mathbf{x} and whose time coordinate is tt.

(c) State the Principle of Galilean Relativity.

(d) Write down the equation of motion for a particle in one dimension xx in a potential V(x)V(x). Prove that energy is conserved. A particle is at position x0x_{0} at time t0t_{0}. Find an expression for time tt as a function of xx in terms of an integral involving VV.

(e) Write down the xx values of any equilibria and state (without justification) whether they are stable or unstable for:

(i) V(x)=(x24)2V(x)=\left(x^{2}-4\right)^{2}

(ii) V(x)=e1/x2V(x)=e^{-1 / x^{2}} for x0x \neq 0 and V(0)=0V(0)=0.