Answer:
The distance between their eye and the ceiling is 33.06 m.
Explanation:
Given that,
The ceiling of a large symphony hall is covered with acoustic tiles which have small holes that are 4.35 mm center to center, D = 4.35 mm
Diameter of the eye of pupil, d = 5.1 mm
Wavelength, 
We need to find the distance between their eye and the ceiling. Using Rayleigh criteria, we get the distance as follows :

So, the distance between their eye and the ceiling is 33.06 m.
This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. ... When air resistance plays a role, the shape of the object becomes important. In air, a feather and a ball do not fall at the same rate.
Answer:
d) Gravity, a normal force, and kinetic friction
Explanation:
- When the bobsledder pushes her sled across horizontal snow to get it going, after she jumps into the sled there acts a force of gravity on the total mass of the sled including the bobsledder.
- The sled moves horizontally and not vertically this means that there is a normal force acting in the vertically upward direction opposite to the gravity.
- While the sled moves on the horizontal surface and comes to the rest there acts a kinetic frictional force on the body in the direction opposite to the direction of motion.