Activity: Feeling the acceleration of Abyss Turbo Drop

Key Learning Points

1. Acceleration
2. Newton's second law
3. Weight
4. Free-body diagram

Introduction

The Abyss Turbo Drop is thrust downwards at a high speed, giving the passengers a thrilling experience of rapid descent. After taking the ride, students will be asked to explain the motion of the ride based on their feeling and their knowledge of physics. The activity is designed to reinforce students' understanding of Newton's second law and its application to an accelerating ride.

How do you feel when taking the Abyss Turbo Drop?

Background knowledge

Basics
• Remind the students of the apparent change in weight inside a lift. In particular, a person would appear to lose weight when the lift is accelerating downwards.
• Let the students imagine what would happen if the cable of the lift breaks. Both the lift and person would fall with a downward acceleration of g, and the person would experience a weightless condition.

Advanced
• Application of Newton's second law to the accelerating lift. Draw free-body diagrams to explain how the net force produces the observed acceleration.

Procedure

Basics
• Take the Abyss Turbo Drop.
• Note the three stages of motion when the ride is thrust downwards. Describe your feeling and note your body weight (a) almost instantly after take off, (b) a second after take off, and (c) shortly before reaching the bottom of the tower.
• Interpret the motion of the ride based on your feeling at each stage. Fill in the worksheet

Advanced
• Draw a free-body diagram which indicates the forces acting on you for each of the three stages. Compare the diagrams with that of a lift accelerating downwards.

Student worksheet

Feeling the first downward thrust

Stage of Motion	Feeling being pulled downwards / weightless / normal / gain weight / lose weight	Interpretation of Motion accelerating / decelerating / moving at a constant velocityacceleration greater than / equals / less than g
Instantly after take off
A second after take off
Shortly before reaching the bottom of the tower

Stage of Motion	Free-body diagram
Instantly after take off
A second after take off
Shortly before reaching the bottom of the tower

Discussion

Basics
• The ride description of the Ocean Park says that the Abyss Turbo Drop will give you "a feeling of negative g, much faster than a free fall". Which stage of the motion does this description apply? What is meant by "negative g"? How do you feel at this stage?
• Have you experienced weightlessness in any stage of the ride? What should be your acceleration in this case?
• How do you feel shortly before reaching the bottom of the tower? Do you have similar feeling (of course milder) when taking a lift?

Advanced
In each of the three stages,
• what is the net force acting on you?
• what is the direction of the force N exerted on you by the ride?
• indicate all the forces acting on you in a free-body diagram.
• compare the magnitude of your true weight mg and the force N exerted on you by the ride.

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