parachutes & drag lo: investigate how area can affect air resistance
TRANSCRIPT
Parachutes & Drag
LO: Investigate how area can affect air resistance
How do parachutes work?
Your investigation• Design and make a parachute to provide
maximum AIR RESISTANCE for your sky-diver (a lump of plasticine)
• Time how long it takes to fall 2m• Repeat the test 3 times• Test three different sizes of parachute• Calculate the average time and speed for each
size parachute
Fill out your results tableSize of parachute (eg: small or 20cm3)
Time taken to fall ___ cm
Time taken to fall ___ cm
Time taken to fall ___ cm
Average Time (seconds)
Speed (s = d/t)
Use your average time for each parachute to work out the speed. Remember that:
Speed = Distance ÷ Time
To work out the average, add all the
times for each activity together and divide by the number of times
you repeated the activity (three)
Questions• Does the change in size of the
parachute make any difference. Why?
• How do the upwards and downwards forces on your parachute change as it descends?
• Would you do a parachute jump?!
Homework - Forces Diagrams
• Draw forces diagrams for a parachutist at three different stages of descent:– Start– Middle – End
• What two forces are acting on the parachutist?• Make sure you label your forces and that the size
of the arrows gives a clear indication of the size of the force
STARTThe parachutist has just
jumped out of the plane and is accelerating very fast
towards the earth!
MIDDLEThe parachutist is now travelling at a constant
speed
ENDThe parachutist has opened
his parachute and has slowed down
Air resistance Air resistance Air resistance
Gravity Gravity Gravity