Seconds squared is the time unit of acceleration. It represents the change in distance units per second per second. For example, 3 m/sec² means a distance covering 3 meters in the first second, then 9 meters in the 2nd second, and 37 meters in the third second. (3^1, 3^2, 3^3).
Acceleration is part of Newton's 2nd law: force = mass x acceleration. Units of work: joule = kg·m²/s², and power: watts = kg·m²/s³ all contain accelerations.
¡Hellow!
For this problem, first, lets convert the seconds in hours:
5,4x10³
5400
h = sec / 3600
h = 5400 s / 3600
h = 1,5
Let's recabe information:
d (Distance) = 386 km
t (Time) = 1,5 h
v (Velocity) = ?
For calculate velocity, let's applicate formula:

Reeplace according we information:
386 km = v * 1,5 h
v = 386 km / 1,5 h
v = 257,33 km/h
The velocity of the train is of <u>257,33 kilometers for hour.</u>
<u></u>
Extra:
For convert km/h to m/s, we divide the velocity of km/h for 3,6:
m/s = km/h / 3,6
Let's reeplace:
m/s = 257,33 km/h / 3,6
m/s = 71,48
¿Good Luck?
To provide a greater certainty that the observed results are not by chance.
GPE=mgh
=25 x 10 x 3
=750J