Answer:
125÷2= 62.5 is your average speed. If the train was resting it's not moving your going nowhere . If the train is traveling at constant speed in a straight line it's speed will increase going through mountains will slow it down. if the train is coming to a braking force its speed will decrease
This is simple question and easy to understand.
so first you use a formula to calculate frequency of the wave.
v _ stands for velocity a.k.a speed
f_ stands for frequency which you have to find.
(pronounced lemda)_ stands for wavelength.
Then you gonna place all your values according to you have in the formula as shown then solve for f.
Finally, you use the time formula
where
T_ is period a.k.a time which equal to the reciprocal of frequency or equal to 1/f.
Simply input your values according to the formula and you your answer as 0.5s