A block of mass is attached to a horizontal spring of force constant on a smooth table

PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

A block of mass 0.50 kg0.50\,\text{kg} is attached to a horizontal spring of force constant 80 N m−180\,\text{N\,m}^{-1} on a smooth table. A dashpot exerts a damping force proportional to the velocity with damping coefficient 4 kg s−14\,\text{kg\,s}^{-1}. A horizontal force F(t)=5cos⁡6t NF(t)=5\cos 6t\,\text{N} acts along the line of the spring. (i) Taking the displacement x(t)x(t) of the block to the right as positive, derive the differential equation of motion of the block. (ii) Write the equation that would govern the motion if the dashpot were removed, and hence obtain the natural angular frequency of the system. (iii) Prove, by performing dimensional checks, that every term in the equation obtained in part (i) has the dimensions of force.

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