Answer:
Part 1) Time of travel equals 61 seconds
Part 2) Maximum speed equals 39.66 m/s.
Explanation:
The final speed of the train when it completes half of it's journey is given by third equation of kinematics as

where
'v' is the final speed
'u' is initial speed
'a' is acceleration of the body
's' is the distance covered
Applying the given values we get

Now the time taken to attain the above velocity can be calculated by the first equation of kinematics as

Since the deceleration is same as acceleration hence the time to stop in the same distance shall be equal to the time taken to accelerate the first half of distance
Thus total time of journey equals
Part b)
the maximum speed is reached at the point when the train ends it's acceleration thus the maximum speed reached by the train equals 
The correct answer is 1.4285714.
In physics, velocity is characterised as a vector measurement of the motion's direction and speed. To be more precise, the rate of change in an object's position relative to a frame of reference and time is another way to describe velocity. The definition of velocity simply states the rate of motion of an object in a specific direction. It determines how quickly or slowly something is going.
Velocity = distance/ time
Thus time = distance/velocity
Here velocity = 350m/s
diatnce = 500 m
time = 500/350
time = 1.42857142857
t= 200m /350m/s = 1.4285714
To learn more about velocity refer the link:
brainly.com/question/18084516
#SPJ9
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
As we know that there is no external torque on the system of two twins
so here we will use



Part b)
Since angular momentum is conserved here as there is no external torque
so we will have



Part c)
Work done by both of them = change in kinetic energy
so we have




Answer:
waves
Explanation:
There are three major ways in which heat or thermal energy is transferred namely: conduction, convection and radiation. Please find the description of each below;
- Conduction is the method of heat transfer which involves a physical contact between the substances involved.
- Convection, on the contrary, occurs via a liquid medium
- RADIATION is a method of heat transfer which involves neither physical contact or liquid medium (matter) but occurs through WAVES e.g electromagnetic waves. For example, the sun transfers heat to the Earth via RADIATION.