A2: Projectile Motion Flashcards
Definition of projectile motion:
The movement of a body through the air following a curved flight path under the force of gravity
What is a projectile?
A body that is launched into the air losing contact with the ground surface (e.g. discus)
What 4 factors affect horizontal distance travelled by a projectile?
Speed of release
Angle of release
Height of release
Aerodynamic factors (Bernoulli & Magnus principles, lift & spin)
How does speed of release affect distance travelled by a projectile?
Greater outgoing speed = Greater distance travelled
How does angle of release affect distance travelled by a projectile?
Optimal release angle = 45 degrees (If release and landing height are equal)
How does height of release affect distance travelled by a projectile?
If release height > landing height, optimal angle < 45 degrees
And vice versa
Definition of parabolic
Uniform curve symmetrical about its highest point
What is a parabolic flight path (and a sporting example)
Flight symmetrical about its highest point caused by the dominant force of weight on a projectile
(E.g. A shot put)
What is a non parabolic flight path (and a sporting example)
Flight path asymmetrical about its highest point caused by the dominant force of air resistance on a projectile
(E.g. a badminton shuttle cock or discus)
Definition of angle of attack
The most favourable angle of release for a projectile to optimise lift force
What is Bernoulli’s principle?
An increase in velocity of air flow occurs simultaneously with a decrease in pressure
How does Bernoulli’s principle create an additional lift force?
All fluids move from high to low pressure (pressure gradient) this creates a lift force which can extend the flight path
How does Bernoulli’s principle work in a downward direction?
If the aerofoil shape is inverted, air is forced underneath the aerofoil to travel a further distance, meaning air velocity is increased underneath, creating low pressure
This causes a down-force, increasing grip and friction
What is a Magnus force?
A force created from a pressure gradient on opposing surfaces of a spinning body moving through the air
What is the Magnus Effect?
An additional Magnus force can deviate a spinning projectile from its projected flight path
What are the 4 types of spin and how do they move differently?
Topspin (Spins downwards, shorter flight path
Backspin (Spins upwards, longer flight path)
Hook (Moves from right to left)
Slice (Moves from left to right)
How does topspin occur?
Eccentric force applied above CoM
How does backspin occur?
Eccentric force applied below CoM
How does a hook occur?
Eccentric force applied to the right of CoM
How does a slice occur?
Eccentric force applied to the left of CoM
Why is spin used in sports like tennis/ table tennis?
To provide stability in flight
To hit the ball harder (topspin -> shorter flight path -> stay in court/ on table)
It can confuse the opposition
