Activity: Displacement-time graph of Abyss Turbo Drop

Key Learning Points

1. Velocity
2. Uniformly accelerated motion
3. Motion graphs

Introduction

Students will analyze the motion of the Abyss Turbo Drop by using the Motion Video Analysis Software  . A displacement-time graph of the motion will be plotted. They will discuss the motion of the ride, divide the motion into several periods, and find out the velocity or acceleration of the ride in each of these periods.

How do you measure the acceleration of the Abyss Turbo Drop?

Background knowledge

Basics
• Motion graphs of uniform motion and uniformly accelerated motion.

Advanced
• Slope of s-t graph = velocity.
• s-t graph of uniformly accelerated motion with non-zero initial velocity.
• Finding velocity and acceleration by curve fitting using a spreadsheet

Procedure

Basics
• Take a look at the ride at a distance. Take a video of motion.
• Use the Motion Video Analysis Software  to plot a s-t graph of the ride.
• Identify the time intervals corresponding to the different stages of the ride's motion. Discuss the motion at each stage.

Advanced
• Export the data using the software. Sort out which part of the data describes the passenger platform when it is (1) travelling upwards initially, (2) thrust downwards for the first time.
• Plot the displacement-time graphs for these two time intervals. Use a spreadsheet (e.g. MS Excel) to fit data set (1) with a straight line and data set (2) with a quadratic curve. It is recommended that only the first 20 m of the first downward thrust is analyzed.
• Discuss the motion for each of these time intervals.
• Find out the velocity and acceleration with the software for each case.

Discussion

Basics
• Identity the time intervals corresponding to the different stages of the motion. Which time interval corresponds to (a) initial rise? (b) brief stop at the top? (c) first downward thrust? (d) subsequent rises and falls?
• In which time interval(s) is the ride (a) travelling at a constant velocity? (b) at rest? (c) accelerating? (d) decelerating?

Advanced
Based on the s-t graphs of (1) the initial rise and (2) the first downward thrust, answer the following questions.
• Is the velocity constant during the initial rise? How do you know? How do you find the velocity of the initial rise?
• How do you find the average acceleration of the first downward thrust?
• Is the acceleration constant when the ride is thrust downwards? How do you know? Fit the data with a cubic curve and discuss the result.

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