The speed of the trolley as it passes through the light gates only shows its speed at that particular moment. The average speed of an object refers to the total distance it travels divided by the time which is elapsed. The physics teacher walked a distance of 12 meters in 24 seconds.
As it moves further down the ramp its speed changes due to acceleration.
If you wanna specify this as a decimal with two significant digits this is going to be so this will approximately equal to 0033. Average speed is the total distance divided by the total time for the trip. Plug the time into the formula. If a cars average speed is 65 miles per hour this means that the cars position will change on the average by 65 miles each hour.