A slope is made by resting one end of a plank of wood on a block, as shown in Fig. 1.1.
Three students each use a digital stopwatch to time a small trolley rolling down the full length
of the slope.
The times on their stopwatches as the trolley reached the bottom of the slope are shown in Fig. 1.2.
On the line next to each stopwatch, write the time measured by each student.