Explanation:
Formula which holds true for a leans with radii
and
and index refraction n is given as follows.
Since, the lens is immersed in liquid with index of refraction
. Therefore, focal length obeys the following.
and,
or,
= 32.4 cm
Using thin lens equation, we will find the focal length as follows.

Hence, image distance can be calculated as follows.


= 47.9 cm
Therefore, we can conclude that the focal length of the lens in water is 47.9 cm.
(a) The plane makes 4.3 revolutions per minute, so it makes a single revolution in
(1 min) / (4.3 rev) ≈ 0.2326 min ≈ 13.95 s ≈ 14 s
(b) The plane completes 1 revolution in about 14 s, so that in this time it travels a distance equal to the circumference of the path:
(2<em>π</em> (23 m)) / (14 s) ≈ 10.3568 m/s ≈ 10 m/s
(c) The plane accelerates toward the center of the path with magnitude
<em>a</em> = (10 m/s)² / (23 m) ≈ 4.6636 m/s² ≈ 4.7 m/s²
(d) By Newton's second law, the tension in the line is
<em>F</em> = (1.3 kg) (4.7 m/s²) ≈ 6.0627 N ≈ 6.1 N
Pressure
= Force/Area
Area = π(d^2)/4
= π(0.4^2)/4
=0.126 m2
Pressure
= 50/0.126
= 396.825 Pa