what would be some safety precautions for this particular experiment

Instruction sheet You will be expected to write a full scientific report for this experiment, so ensure that you take note of all the procedures and findings. Instructions 1. Place two trolleys, one of which contains a compressed spring, against each other on a smooth, horizontal floor. 2. Place another trolley on top of one of the trolleys in step 1. These two trolleys now represent a mass of 2m, while the single trolley represents a mass of 1m. 3. Place two sturdy wooden planks as barriers on either side of the track (not further than 1-1,5m from the centre of the track) as shown in the diagram below. 4. Release the spring of one trolley so that the two trolleys move apart. Listen to the sound of the collisions against the barrier/buffer. The trolleys hit the wooden planks at different times, because one trolley moves more slowly than the other one (different velocities). wwww 5. By means of trial and error, find a position from which the trolleys move so that both trolleys will hit the wooden planks on both sides at the same time. Only a single collision should be heard. 2