All Problems

Mechanical Oscillations

Problem 4.3

A particle performs harmonic oscillations along the xx axis about the equilibrium position x=0x=0. The oscillation frequency is ω=4.00 s1.\omega=4.00 \mathrm{~s}^{-1} . At a certain moment of time the particle has a coordinate x0=25.0 cmx_{0}=25.0 \mathrm{~cm} and its velocity is equal to vx0=100 cm/sv_{x 0}=100 \mathrm{~cm} / \mathrm{s} Find the coordinate xx and the velocity vxv_{x} of the particle t=2.40 st=2.40 \mathrm{~s} after that moment.

Reveal Answer
 4.3. x=acos(ωt+α)=29 cm,vx=81 cm/s, where a=x02+(vx0/ω)2,α=arctan(vx0/ωx0)\begin{aligned} &\text { 4.3. } x=a \cos (\omega t+\alpha)=-29 \mathrm{~cm}, \quad v_{x}=-81 \mathrm{~cm} / \mathrm{s}, \text { where }\\ &a=\sqrt{x_{0}^{2}+\left(v_{x 0} / \omega\right)^{2}}, \alpha=\arctan \left(-v_{x 0} / \omega x_{0}\right) \end{aligned}