Answer:

Explanation:
Given:
mass of person, 
mass of merry go-round, 
radius of merry go-round, 
velocity of the person running, 
<u>We consider merry go-round as a ring:</u>
Now the moment of inertial of the ring is given as,



<u>Moment of inertia of the person considering as a point mass:</u>



<u>Now according to the conservation of angular momentum:</u>

where:
angular velocity of the merry-go-round
angular velocity of the person running



Many of today’s mathematicians use computers to test cases that are either too time-consuming or involve too many variables to test manually, allowing the exploration of theoretical issues that were impossible to test a generation ago.
Answer: Option A
<u>Explanation:</u>
One of the most useful inventions in scientific world are the computers. We can use different programming language and create programs in them. These programs help other to solve difficult problems. Most of the theoretical problems in science can be solved by using these programming features in computer within a specific time limit.
Otherwise, earlier mathematician used to take months to solve a complex mathematical problem manually, but now with the inclusion of computers, the mathematician can solve the problems containing more number of variables or other theoretical issues.
Answer:
B) The tree was stationary and began to move.
Explanation:
This situation can be explained by using Newton's first law of motion, which states that
"An object at rest (or in motion at constant velocity) stays at rest (or in motion at constant velocity) unless a net non-zero force is exerted on it"
This means that an object at rest can start moving if and only if there is a net non-zero force acting on it.
In the example in the problem, the tree is initially stationary. Later, it started to move. According to Newton's first law, therefore, there must be a net force that caused this change of state of motion of the tree. Therefore, the correct answer is
B) The tree was stationary and began to move.
Answer:
weight!!!! Free fall is the motion of a body where its weight is the only force acting on an object.