An example of a system with decreasing gravitational potential energy is a ball in free fall.
At its initial height h, the ball has a gravitational potential energy equal to

where m is the ball mass and g is the gravitational acceleration. As the ball falls toward the ground, its height h decreases, and so its gravitational potential energy decreases as well, according to the formula

where h' is the new height of the ball.
We all think that sleep has a uniform state of being. This is a wrong connotation but instead, the truth is sleep is composed of several different stages. This can be differentiated from one another by the patterns of brain wave activity that occur during each stage. In the 1st stage of the non-rapid eye movement or NREM, this is when the transitional phase occurs between wakefulness and sleep. This is the period when we drift off to sleep. The heartbeat as well as the respiration rates in the body slow down during this period. Furthermore, in stage 1 there is marked decrease in both overall muscle tension and core body temperature. Stage 1 wave activity s directly associated with the alpha and theta waves. It isa said that it is really easy to wake a person who is still at stage 1 and are not even convinced that he or she has been asleep during this stage.
They are positive and remain inside the nucleus.
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 