To solve the problem, it is necessary to apply the concepts related to the change of mass flow for both entry and exit.
The general formula is defined by

Where,
mass flow rate
Density
V = Velocity
Our values are divided by inlet(1) and outlet(2) by





PART A) Applying the flow equation we have to



PART B) For the exit area we need to arrange the equation in function of Area, that is



Therefore the Area at the end is 
The contact force is indeed caused by "Contact".
Air resistance is basically a type of friction, which is apparently present providing two object contact.
The rest selections are all interaction force, which is not necessarily caused by contact.
Answer:
Ossicles
Explanation:
Sound causes eardrums to vibrate. These vibrations are then passed on to the ossicles, which is made up of 3 small bones-- the malleus, incus, and stapes. The stapes are connected to the inner ear, specifically to the cochlea which transforms sound waves into electrical signals that are sent to the brain.
Answer:
a ) 1.267 radian
b ) 1.084 10⁻³ mm
Explanation:
Distance of screen D = 1.65 m
Width of slit d = ?
Wave length of light λ = 687 nm.
Distance of second minimum fro centre y = 2.09 cm
Angle of diffraction = y / D
= 2.09 /1.65
= 1.267. radian
Angle of diffraction of second minimum
= 2 λ / d
so 2 λ / d = 1.267
d = 2 λ / 1.267 = (2 x 687 ) /1.267 nm
=1084.45 nm = 1.084 x 10⁻³ mm.