The method and the results are on the average speed lab. Do the analysis yourself first, then check the answers below.
Quick answer: Average speed is the total distance an object travels divided by the total time it takes, written v = d ÷ t. These answers go with the grade 6 science lab on average speed: the graph, the calculations, the uncertainties and the conclusion explained, for all 7 analysis questions.
The sample data give a speed close to 0.38 m/s for every distance and a straight line through the origin. Compare your own values with these answers and explain any differences using the uncertainty in timing.
The points lie close to a straight line through the origin. This shows that the car moves at an almost constant speed once it leaves the ramp.
Question 4 Gradient
Gradient = 2.00 ÷ 5.24 = 0.382 m/s. The mean of the four speeds is (0.382 + 0.385 + 0.380 + 0.382) ÷ 4 = 1.529 ÷ 4 = 0.382 m/s, so the two values agree.
Question 5 Timing error
0.1 ÷ 1.31 × 100 = 7.6 %; 0.1 ÷ 5.24 × 100 = 1.9 %. The longer distance gives the smaller percentage uncertainty, so it is better.
Question 6 Prediction
t = d ÷ v = 3.00 ÷ 0.382 = 7.85 s, so about 7.9 s.
Question 7 Improvements
Use a light gate or phone video with a frame counter instead of a hand-held stopwatch, and repeat more times, ignoring any result far from the others. Using a longer track also reduces the effect of reaction time.
