1 aeroplanes need wings.) - npl.co.uk · brochure, without notice. The NPL name and logo are owned...
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npl.co.uk © NPL Management Ltd, 2019. 12415/0119 Disclaimer Although every effort is made to ensure that the information contained in this brochure is accurate and up to date, NPL does not make any representations or warranties, whether express, implied by law or by statute, as to its accuracy, completeness or reliability. NPL excludes all liabilities arising from the use of this brochure to the fullest extent permissible by law. NPL reserves the right at any time to make changes to the material, or discontinue the brochure, without notice. The NPL name and logo are owned by NPL Management Limited. Any use of any logos must be authorised in writing. The National Physical Laboratory (NPL) hosts the longest-running water rocket competition in the world and has also built the world’s largest water rocket. Check out npl.co.uk/wrc Did you know? Answers: 1. Rockets are launched upwards • Wings give lift • 2. Possibly • 3. We can cope with the force due to air pressure but an elephant would double the force - squashing us! The rocket forces propellant (gas/liquid) backwards and an equal and opposite force pushes the rocket forwards. The amount of thrust is influenced by the rate at which water leaves the bottle and depends on: - Pressure: the higher the pressure the faster the water leaves. - Nozzle design: bigger nozzles with streamlined necks allow water to leave the bottle more easily. Thrust If you spray a hose-pipe while sitting on a skateboard, will you move? 2 The ‘bar’ is a unit measuring air pressure (1 bar is about 1 kg/cm 2 ). A reading of 1 bar means an additional bottle’s worth of air is squeezed in, etc. Higher pressure means more stored energy. Fizzy drinks bottles explode beyond 7 bar. Pressure 1 kg/cm 2 is about the pressure of an elephant on the ground. Why would we notice an elephant standing on us, but we don’t notice the air? 3 Friction in the launcher can slow launch. Thrust is the push from water and air leaving the rocket, propelling it forwards. Weight is the force on the rocket due to Earth’s gravity. Air resistance (drag) slows the rocket down. Forces on the rocket Which directions do these forces act in, and how do these directions change during flight? (Maybe this gives you a clue about why aeroplanes need wings.) 1 Thrust Friction Drag Weight Which rocket do you think will go the furthest and why? Shape Forces on water rockets The NPL Water Rocket Challenge is to land a rocket at a range of 70 m ± 5 m
Transcript of 1 aeroplanes need wings.) - npl.co.uk · brochure, without notice. The NPL name and logo are owned...
npl.co.uk© NPL Management Ltd, 2019. 12415/0119
Disclaimer Although every e� ort is made to ensure that the information contained in this brochure is accurate and up to date, NPL does not make any representations or warranties, whether express, implied by law or by statute, as to its accuracy, completeness or reliability. NPL excludes all liabilities arising from the use of this brochure to the fullest extent permissible by law. NPL reserves the right at any time to make changes to the material, or discontinue the brochure, without notice. The NPL name and logo are owned by NPL Management Limited. Any use of any logos must be authorised in writing.
The National Physical Laboratory (NPL) hosts the longest-running water rocket competition in the world and has also built the world’s largest water rocket.
Check out npl.co.uk/wrc
Did you know?
Answers:
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2. P
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The rocket forces propellant (gas/liquid) backwards and an equal and opposite force pushes the rocket forwards.
The amount of thrust is in� uenced by the rate at which water leaves the bottle and depends on:
- Pressure: the higher the pressure the faster the water leaves.- Nozzle design: bigger nozzles with streamlined necks allow
water to leave the bottle more easily.
Thrust
If you spray a hose-pipe while sitting on a skateboard, will you move?2
The ‘bar’ is a unit measuring air pressure (1 bar is about 1 kg/cm2).
A reading of 1 bar means an additional bottle’s worth of air is squeezed in, etc.
Higher pressure means more stored energy.
Fizzy drinks bottles explode beyond 7 bar.
Pressure
1 kg/cm2 is about the pressure of an elephant on the ground. Why would we notice an elephant standing on us, but we don’t notice the air?3
Friction in the launcher can slow launch.
Thrust is the push from water and air leaving the rocket, propelling it forwards.
Weight is the force on the rocket due to Earth’s gravity.
Air resistance (drag) slows the rocket down.
Forces on the rocket
Which directions do these forces act in, and how do these directions change during � ight? (Maybe this gives you a clue about why aeroplanes need wings.)1
Thrust
FrictionDrag
Weight
Which rocket do you think will go the furthest and why?
Shape
Forces on water rocketsThe NPL Water Rocket Challenge is to land a rocket at a range of 70 m ± 5 m
