A student investigates the average speed of a trolley moving along a horizontal bench. The trolley is placed on a ramp and released from rest. Some of the apparatus used is shown in Fig. 4.1. [Figure 4.1] The stopping distance of the trolley is the distance moved by the trolley from the bottom of the ramp until it comes to rest. Plan an experiment to investigate how the average speed of the trolley along the bench until it comes to rest depends upon its mass. The average speed of the trolley can be calculated using the equation shown. average speed = stopping distance / time You are not required to do this experiment. In your plan you should: • explain briefly how to carry out the investigation, stating any other apparatus needed • state the key variables to keep constant • draw a table with column headings to show how to display the readings (you are not required to enter any readings into the table) • explain how to use your readings to reach a conclusion. [6]