In which situation can you be at rest and moving at the same time?

when playing soccer, you are at rest relative to the ball and moving relative to the field.

when swimming, you are at rest relative to the water and moving relative to the sides of the pool.

when riding a bike, you are at rest relative to the bicycle and moving relative to the road

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)