Final answer:
The motion of a ball on a table involves forces like the push from the ruler, friction, gravity, and the normal force from the table. If launched vertically, gravity affects its vertical motion, while friction affects its horizontal motion. Clearly labeled graphs are essential for analyzing motion in experiments.
Step-by-step explanation:
When a ball moves on a table after being touched by a ruler, it experiences several forces. Initially, the ruler exerts a force on the ball to set it in motion. Once the ball is moving on the table, it is subject to friction, which acts in the opposite direction of its movement, gradually slowing it down. If the table is perfectly horizontal, there would be no gravitational force causing the ball to accelerate in any lateral direction, but gravity would still act downward while the normal force from the table's surface supports the ball, preventing it from falling through.
If the ball is launched vertically upward, as in a different part of the example, the forces involved include the initial upward force that sets it in motion and gravity, which will slow the ball down until it stops momentarily at its peak height before accelerating it back downward. During this motion, air resistance might also act on the ball, albeit this may be negligible depending on the context given.
As for the direction of forces, according to Newton's First Law, frictional force acts opposite to the direction of motion, so if a ball rolls from north to south, the frictional force would be directed from south to north.
In experiments where motion is analyzed, for example, with a marble rolling down a ruler and then across a table, or pushing a book to observe it slow down, it's important to clearly label the graphs with appropriate values and units to depict the book's position vs. time and velocity vs. time. For the ball or marble, the graph of its horizontal velocity over time would typically show a decreasing velocity due to friction, unless other forces are applied.
If the ball bounces while moving forward, its motion will be a combination of the linear motion forward and the vertical motion due to bouncing. The resultant motion would be a parabolic trajectory as viewed from the side. Any plot of velocity squared versus distance traveled should result in a straight line if kinetic energy is proportional to potential energy, indicating conservation of energy in the system.