91Ó°ÊÓ

• The graph starts when the cart is at rest and ends when the cart is again at rest

The difference between final and beginning momentum levels is called the change in momentum.The change in momentum is equal to the impulse.

The change of momentum can be given as,

$F_{net=∆p∆t}$

The area under force and time gives the change in momentum.

The first experiment is the initial state of the cart. Give it a little nudge, and it coasts for a long time in the +x direction down the track, eventually stopping.This situation can be depicted using graph 6.

In the second experiment the fan is turned on but the cart is held stationary and in some while when the hold is removed the cart starts to move in the +x direction the cart is stopped suddenly and it eventually comes to rest. This situation can be depicted using graph 7.

In the third experiment,the fan is facing the wrong direction initially the cart was held at rest. A brief push was given and it starts moving in +x direction, it slows down and returns to the starting position where the cart is held and stopped. The situation can be depicted using graph 5.

Thus, the graphsare being identified according to the experiment.