Answer:
(a) Time t = 16.46 sec
(b) Time t =13.466 sec
(c) Deceleration = 
Explanation:
(a) As the train starts from rest its initial velocity u = 0 m/sec
Acceleration 
Final speed v = 80 km/hr

From first equation of motion v =u+at
So 
(b) Now initial speed u = 22.22 m/sec
As finally train comes to rest so final speed v=0 m/sec
Deceleration 
So 
(c) We have given that initial velocity = 80 km/hr = 22.22 m/sec
Final velocity v = 0 m/sec
Time t = 8.30 sec
So acceleration is given by

As acceleration is negative so it is a deceleration
We are given with
distance traveled through vacuum = 1.0 m
refractive index of water = 1.33
refractive index of glass = 1.50
refractive index of diamond = 2.42
distance traveled through water is = 1.0/1.33 = 0.75 m
distance traveled through water is = 1.0/1.50 = 0.67 m
distance traveled through water is = 1.0/2.42 = 0.41 m
"Dispersion forces" is the one intermolecular force among the following choices given in the question that <span>explains why iodine (I2) is a solid at room temperature. The correct option among all the options that are given in the question is the third option or the penultimate option. I hope that the answer has helped you.</span>
transverse and longitudinal
The concave mirror is a spherical-shaped mirror that has an inner curved surface. Hence, option (4) is correct.
What is a concave mirror?
The concave mirrors are spherical-shaped mirrors that are painted on the outward surface. It is also known as the converging mirror, having the recessed inner reflecting surface.
- The concave mirrors are generally used for the purpose to focus the light. For that, they might have a reflecting surface, curved inwards, and the reflection of light is limited to the single focal point.
- The reflecting surface of the concave mirror has its vertex or midpoint lying farther away from the objects than the edges.
Thus, we can conclude that the surface of the concave mirror is curved inward. Hence, option (4) is correct.
Learn more about the concave mirror here:
brainly.com/question/13300307