The answer is a Viscosity because it describes the internal friction of a moving liquid
Answer:
(a) 40.6 degree
Explanation:
When refraction takes place from slab to water, the critical angle is 60 degree.
Use Snell's law
refractive index of water with respect to slab



μs = 1.536
Now for slab air interface, the critical angle is C.


1 / 1.536 = Sin C
C = 40.6 degree
Not so fast.
I think you're using 'accelerating' to mean 'speeding up', but you really need
to be more careful with it. "Acceleration" means ANY change in speed OR
direction.
If an object's speed to the left is decreasing, or its speed to the right is
increasing, then the net force on the object must be directed towards
the right.
If an object is moving with constant speed in a circular path, then it's
constantly accelerating, because its direction is constantly changing.
The force on it is always directed towards the center of the circle, so
there's one point on the path where the force is directed straight to the right.