Answer:

Explanation:
As we know that train is initially moving with the speed

now we know that

now the final speed of the train when it crossed the crossing


now we can use kinematics here



Now the time to cross that junction is given as



Answer:
Part a) 
Part b) 
Explanation:
Part a) what is its frequency, in rev/s
we have that
An old-fashioned LP record rotates at 33 1/3 RPM
so

Convert mixed number to an improper fraction

Remember that

Convert rev/min to rev/sec

Simplify

Part b) what is it period, in seconds
we know that
The period is the reciprocal of the frequency
therefore
the frequency is

Explanation:
It is given that,
The acceleration of the toboggan, 
Initial speed of the toboggan, u = 0
We need to find the distance covered by the toboggan. Using the second equation of motion as :

At t = 1 s


At t = 2 s


At t = 3 s


Hence, this is the required solution.