A searchlight revolving once each minute is located at a distance of 1/4 mile from a straight beach. How fast is the light moving along the beach when the beam makes an angle of 60° with the shore line?

Answer 1

x/(1/4) = tanθ

4 dx/dt = sec^2θ dθ/dt

now just plug in your numbers. Careful with the units.

Answer 2

Thank you so much Sir!