Part 1)

"A simple pendulum consists of a mass m hanging from a string of length L and fixed at a pivot point P. When displaced to an initial angle and released, the pendulum will swing back and forth with periodic motion. By applying Newton's second law for rotational systems, the equation of motion for the pendulum may be obtained"

In Python, assign this text paragraph above to as string named tstring. Write a line of Python to return the length of this string.

Part 2)

Write a single line of Python that returns the number of times the substring si occurs in tstring. What are the locations of these occurrences in the string (position numbers)?

Part 3)

Create a new string named ustring which is every fourth letter from the reversed (backwards) tstring.