Learners investigate the relationship between net force and acceleration by pulling a trolley across a surface which is slightly inclined to compensate for friction. The trolley is connected to different masses by a string of negligible mass. The string passes over a frictionless pulley. Refer to the diagram below.

Ticker-tape attached to the trolley passes through the ticker-timer. The acceleration of the trolley is determined by analysing the ticker-tape. The results of the net force produced by the different masses and the acceleration of the trolley were recorded in the table below.

3.1 Write down a hypothesis for this experiment. (2)
3.2.1 Identify the independent variable. (1)
3.2.2 Identify the controlled variable. (1)
3.3 Use the graph paper on the ANSWER SHEET and draw a graph of the acceleration versus net force. (4)
3.4 Calculate the gradient of the graph. (3)
3.5 Use the gradient of the graph calculated in QUESTION 3.4 to determine the mass of the trolley. (2)
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