What is the primary purpose of using a 1.25L Coke bottle as the body of a bottle rocket?

• To provide a lightweight structure

• To ensure the rocket is colourful

• To make the rocket more aerodynamic

• To increase the rocket's weight

Answer explanation

The primary purpose of using a 1.25L Coke bottle is to provide a lightweight structure, which is essential for the rocket to achieve higher altitudes with less weight, allowing for better propulsion and flight performance.

Why is a tennis ball used as the nose cone for a bottle rocket?

• It adds extra weight to the rocket

• It helps to stabilise the rocket during flight

• It makes the rocket look more appealing

• It increases the rocket's speed

Answer explanation

A tennis ball as a nose cone helps to stabilise the rocket during flight by providing a rounded shape that reduces drag and improves aerodynamics, ensuring a smoother trajectory.

What is the role of 3mm coreflute fins on a bottle rocket?

• To make the rocket heavier

• To stabilise the rocket and improve its flight path

• To increase the rocket's speed

• To make the rocket more colourful

Answer explanation

The 3mm coreflute fins on a bottle rocket are designed to stabilise the rocket during flight, ensuring a straighter and more controlled trajectory. This helps improve its overall flight path.

What happens to the centre of mass when you add a tennis ball as a nose cone?

• It moves towards the bottom of the rocket

• It remains unchanged

• It moves towards the top of the rocket

• It moves to the middle of the rocket

Answer explanation

Adding a tennis ball as a nose cone increases the mass at the top of the rocket, causing the center of mass to shift upwards. Therefore, the correct answer is that it moves towards the top of the rocket.

What is the centre of pressure in a bottle rocket?

• The point where the rocket's weight is concentrated

• The point where aerodynamic forces are balanced

• The point where the rocket's speed is maximum

• The point where the rocket's volume is maximum

Answer explanation

The centre of pressure is the point where aerodynamic forces acting on the rocket are balanced, ensuring stable flight. This is crucial for maintaining the rocket's trajectory during ascent.

How does a bottle rocket perform without a nose cone and fins?

• It flies in a straight line

• It becomes unstable and wobbles

• It flies faster

• It does not launch

Answer explanation

Without a nose cone and fins, a bottle rocket lacks stability, causing it to become unstable and wobble during flight. The fins and nose cone are essential for maintaining a straight trajectory.

What is the effect of removing fins from a bottle rocket?

• The rocket becomes more stable

• The rocket becomes less stable

• The rocket flies higher

• The rocket flies slower

Answer explanation

Removing fins from a bottle rocket decreases its stability. Fins help maintain a straight flight path by providing aerodynamic control. Without them, the rocket is more likely to wobble or veer off course.

How does the volume of water (400ml vs 450ml vs 500ml) affect the performance of a bottle rocket?

• More water always makes the rocket fly higher

• Less water always makes the rocket fly higher

• The optimal amount of water needs to be balanced for best performance

• Water volume does not affect the rocket's performance

Answer explanation

The optimal amount of water needs to be balanced for best performance because too much or too little can affect thrust and stability, impacting the rocket's height. Finding the right volume is key to maximizing flight performance.

What is the impact of increasing air pressure from 60psi to 80psi on a bottle rocket?

• The rocket flies lower

• The rocket flies higher

• The rocket's speed decreases

• The rocket's stability decreases

Answer explanation

Increasing air pressure from 60psi to 80psi provides more force for propulsion, allowing the rocket to fly higher. Higher pressure means more potential energy is converted to kinetic energy, resulting in greater altitude.

What is the ideal launch angle for a bottle rocket to achieve maximum distance?

• 30 degrees

• 45 degrees

• 60 degrees

• 90 degrees

Answer explanation

The ideal launch angle for a bottle rocket to achieve maximum distance is 45 degrees. This angle optimally balances vertical and horizontal motion, maximizing the range of the rocket.