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
It is an example of rolling friction because balls roll.
Answer is ROLLING
Answer:
The well is 7.1 meters deep.
Explanation:
The formula to use here is the distance in a uniformly accelerated motion:

where d stands for distance, t for time, a for acceleration, v0 and d0 for initial velocity and distance, respectively. Since the initial distance and velocity are both zero, we are left with the first term. The coin is in free fall and so it is accelerated by gravity:

The well is 7.1 meters deep.
Answer: heat
Insulation Traps Heat. Keeping the cold air out
Explanation:
Answer:
223.25
Explanation:
The thermal conductivity of an object is defined as the measure or the ability of the object to transfer heat or conduct heat through its body.
In the context, the thermal conductivity of the material is given as

And it is given that :
1 Btu = 1055 J
1 ft = 0.3048 m

We know that 1 h = 3600 s
So the thermal conductivity of the material in
is :
Thermal conductivity :


= 223.25