Answer:
Explanation:
Given
Radius of bicycle wheel 
Initial angular velocity 
It rotates 3 revolution in 5 s therefore

using 
where 



Total acceleration of any point will be a vector sum of tangential acceleration and centripetal acceleration




Tangential acceleration 




A) An electrical resistor
Hope that helps, Good luck! (:
Explanation:
(a)
Critical angle is the angle at the angle of refraction is 90°. After the critical angle, no refraction takes place.
Using Snell's law as:
Where,
is the angle of incidence
is the angle of refraction = 90°
is the refractive index of the refraction medium
is the refractive index of the incidence medium
Thus,
The formula for the calculation of critical angle is:
Where,
is the critical angle
(b)
No it cannot occur. It only occur when the light ray bends away from the normal which means that when it travels from denser to rarer medium.