Forces: Projectile motion Flashcards
are forces:
A) scalars
B) vectors
Vectors
Name 2 horizontal forces
- friction
- Air resistance
What does the size of the arrow mean on a free body diagram?
The magnitude/size of the force
What are balanced forces?
Vertical and horizontal forces are equal to each other
What are unbalanced forces?
One of the forces is unequal (larger or smaller than the other)
What is meant by the net force?
the summary of all the forces in action
Describe a vector diagram for long jump
- large internal muscular force from the legs to produce a big action force
- more vertical force than horizontal force produced by the muscles
- results in a high trajectory
What is gravity?
What way does gravity act?
How does it affect a performer?
- gravity is the force pulling the performer to the ground
- Acts vertically
- This speeds up the falling of the performer
- works in the same direction as motion
What is air resistance? (AR)
What way does this force act?
How does it affect a performer?
- AR is the force applied by the air on bodies that are moving through it
- acts both horizontally and vertically
- It affects the performer because it slows the performer down
- acts in the opposite direction to motion
What is friction?
What way does this force act?
How does it affect a performer?
- friction is when two surface slide against each other
- Acts horizontally
- prevents performer slipping and sliding
How can we increase friction?
- rougher surfaces
- increase the mass of performer
- increase surface area
What are the 2 types of friction?
- static - friction before an object starts to slide
- sliding - friction when an object is moving
What is reaction force?
What way does this force act?
- occurs when you push off a surface
- acts horizontally and vertically
- acts in the same direction as the motion
What is muscular action force?
How does this force act?
- causes motion as it acts internally
- acts horizontally and vertically
what are the factors affecting gravity?
mass of body
what are the factors affecting air resistance?
- the cross sectional area of the body
- speed of the body
what are the factors affecting friction?
roughness of a surface
What are the factors affecting reaction force and muscular action?
Physiology e.g muscle innervation, muscle fibre types, motor neuron recruitment etc
What is projectile motion?
movement of an object/human body as it travels through the air
What is horizontal displacement?
Shortest distance from start point to finish point in a line parallel to the ground.
What are the factors affecting projectile motion?
- angle of release
- hight of release
- speed or release
Angle of release AO1
- ensures body travels as far as possible
- Optimum angle of release is 45 degrees, both hight of release and landing release are equal.
What happens when the release hight below the landing hight?
- angle of release has to be greater than 45 degrees
what happens when the release hight is higher than landing hight?
- angle of release less than 45 degrees
Speed of release AO1
- greater the release velocity, the greater the horizontal displacement
Height of release AO1
- Greater the release hight increases horizontal displacement
How does the height of release affect a shot put?
- Gravity constantly acting on the shot put
Performer should release at the highest point possible to gain max displacement.
What are factors affecting flight paths of projectiles?
- weight
- AR
These are crucial in deciding if the projectile has a true parabola or a distorted parabola
What is true of parabolas and and large weight forces
These projectiles which have a large weight force have small air resistance and follow true parabolic flight
How would speed of release affect a shot put?
the speed across the circle (preparation phase) ensures the shot put leaves with max velocity, causing greater horizontal displacement.
give an example where the release height is is below the landing hight
basketball - shooting a hoop if the ring is the landing height
give an example where the release hight is above the landing hight
in shot put where the hand is the point of release which is above the landing point (ground)
What happens when a projectile has lighter mass in terms of parabola?
- AR means that it deviates from a true parabolic flight path to a deviated parabolic flight path
How would parabola be applied to a shuttlecock?
- Shuttlecock has lighter mass
- ” unusual shape which increases AR
- starts off with high velocity via the force of the racket
- velocity decreases as AR reduces
