On the physical aspect of XT graph In XT graph, when the line in the graph starts from zero, it moves up first. When it reaches a point, it moves down again. When v reaches zero, it continues to fall below zero. When it goes up, it's a positive speed. I don't know if the zero point is turning around from time to time when I go down. If it's below zero point, it's back to the starting point and moving in another direction Compulsory one in senior one

On the physical aspect of XT graph In XT graph, when the line in the graph starts from zero, it moves up first. When it reaches a point, it moves down again. When v reaches zero, it continues to fall below zero. When it goes up, it's a positive speed. I don't know if the zero point is turning around from time to time when I go down. If it's below zero point, it's back to the starting point and moving in another direction Compulsory one in senior one

according to
Because it's straight up and down, so
x=kt
Then v = k is obtained
x=Vt
The slope of ascending section is positive
Speed is also in the positive direction
The slope of descending section is negative
The velocity is negative
When x reaches the maximum~
Speed changes direction!