FM1 - Terminal velocity Flashcards
What is free fall?
When an object is falling with no driving force (other than gravity) acting on it
Give an example of a free falling object
A fluid eg air as it will eventually reach terminal velocity
Describe how free fallers reach terminal velocity
1) Bigger force accelerating them than resistance
2) As velocity increases, resistance increases
3) Gradually acceleration is reduced
4) Resistance force = accelerating force - cant accelerate anymore
5) It has reached maximum velocity (terminal velocity)
What does the terminal velocity of an object depend on?
Their size and area
What is the accelerating force acting on all objects? and why do they not travel at the same rate?
Gravity and because of air resistance
How can you prove that air resistance effects objects fallling at the same rate?
- On the moon because their is no air, hamsters and feathers were dropped simultaneously and hit the ground together.
- On earth air resistance causes things to fall at different speeds and terminal velocity is determined by its drag compared to weight. Drag depends on its shape and area
Give an example of terminal velocity and how shape and area effects it?
A human skydiver - without the parachute open he has a small area and force equal to his weight pulling him down. He reaches a terminal velocity of 120 mph. However with the parachute open theres more air resistance and still the same force pulling him down meaning that his terminal velocity goes down to 15 mph which is much safer for landing
What can you use to investigate free fall and why?
Sycamore seeds because they have a small weight and a large surface area so will reach terminal velocity really quickly and will fall slowly
What sycamore seeds should you collect? and what do you do with them?
Seeds of different sizes - mass and wing length should be measured. Use seeds with similar mass but different wing lengths
Describe the sycamore experiment after collecting and measuring them accurately
Drop each one from similar heights and time how long it takes for one to hit the floor (The higher you drop them from the better) Repeat the experiment the experiment for each seeds and find the average
What can you do after recoding your results from the sycamore experiment?
Plot a graph of the length of wings against time taken to hit the ground
Should there be a relationship between the shape and their terminal velocity?
Yes - bigger wings means bigger surface area so higher drag. Higher drag means lower terminal velocity and so slower free fall (graph should show a diagonal straight line going up)
