The Montgolfier brothers (Joseph and Etienne) were 18th century pioneers in the field of hot-air ballooning. Had they had appropriate instruments, they might have left us a record of one of their...

The Montgolfier brothers (Joseph and Etienne) were 18th century pioneers in the field of
hot-air ballooning. Had they had appropriate instruments, they might have left us a
record of one of their early experiments, like the flight shown below. The graph is of their
vertical velocity, v, with upwards as positive.




Before answering the questions, the graph (should be given along with question,
however same was not given and adopted from internet. If your graph is different to this,
the explanation will help you to do it ion your own) is explained. It is assumed that the
flight has started from the ground level. It is a velocity versus time graph and upward
direction is considered to be positive. The slope of the velocity vs time graph represents
the accelerations and the area underneath the graph gives the displacement. Between t
= 0 to t = 45, the velocity is positive, means the object is moving in upward direction.
From t = 0 to t = 40, the slope of the graph is positive, means it is accelerating and
reached to its top velocity at t = 40 min. at t = 40 min, the object starts decelerating
however it...