a submarine is observed to rise from a real depth of 80 m to 60 m in water calculate the change in apparent depth

15m

Explanation:

change in real depth = 80 - 60 = 20m

Let us assume that the index is 4/3

Refractive index = change in real depth ÷ change in apparent depth

change in apparent depth = change in real depth÷ refractive index

= 20÷(4/3) = 20×(3/4) = 5×3 = 15m

15.3 cos 65 degrees trig

grav forces affect all objects magnetic forces affect magnetic objects and electric currents