Projectiles

Question 1

What is a projectile

Answer 1

A body that is moving within a fluid, not in contact with the ground. Fluids contain air and water

Question 2

What effects the horizontal distance that a projectile travels before landing

Answer 2

1. Height of release- the higher the height of release from the landing height, the further the horizontal height travelled. Eg in golf a raised tee height, ball travels further before landing.
2. Speed of release- how fast the body is travelling before it becomes a projectile. Eg a faster arm throw in javelin
3. Angle of release- optimum angle 45 degrees if the height of release is the same as the landing height, if landing height is lower than optimum angle is less than 45 degrees. Eg shot-put

Question 3

Once in flight, what are the two forces that act on a projectile

Answer 3

WEIGHT AND AIR RESISTANCE

Question 4

What is a projectile

Answer 4

A body moving within a fluid, not in contact with the ground. Fluids include air and liquid

Question 5

How do we work out the resultant force for a projectile

Answer 5

Draw the weight and air resistance arrows on the diagram, and then draw a parallelogram, draw a dotted line from the origin.

Question 6

What is a parabola

Answer 6

A uniform curve that is symmetrical about its highest point

Question 7

What is a non- parabolic

Answer 7

A curve that is NOT symmetrical (asymmetrical) about its highest point

Question 8

What does the shape of the flight path depend on

Answer 8

The relative size of the TWO FORCES ACTING : WEIGHT AND AIR RESISTANCE

Question 9

When is the flight path parabolic

Answer 9

When WEIGHT is the dominant force(body has a large mass), and there is little air resistance Eg shot put

Question 10

When is the flightpath non parabolic

Answer 10

If the WEIGHT IS SMALL and the AIR RESISTANCE IS LARGE eg a Badminton shuttle
This is because the air resistance is able to overcome the small mass, and decrease its velocity

Question 11

What is a airofoil

Answer 11

Streamline structure with at least one curved surface.
Aerofoils can be symmetrical- javelin or discus OR asymmetrical- ski jumper or F1 car spoiler

Question 12

What is the angle of attack

Answer 12

The angle at which a projectile is presented or tilted to the air

Question 13

What is Bernoullis principle

Answer 13

The faster the fluids flow, the less pressure they exert. The slower that fluids flow the more pressure they exert. This can create a lift force on a projectile

Question 14

Does air trace after or slower over the projectile

Answer 14

FURTHER=FASTER= LOW PRESSURE
SHORTER DISTANCE= SLOWER= HIGH PRESSURE

Question 15

What is the impact of an upward force

Answer 15

Reduces impact of weight
Resultant force has a smaller downward arrow
Flight time extended and therefore the horizontal distance increases
He flight path made is non parabolic

Question 16

What is a reverse airfoil

Answer 16

An aerofoil with a curved surface facing downward, and its flatter surface is facing upward, it causes downforce. Eg F1 car racing car.
Air moving further=faster= lower pressure
Shorter=slower=higher

Question 18

What is a eccentric force

Answer 18

A force outside the centre of mass of a body (or a off centre force)
An eccentric force initiates spin Eg sliced backhand in tennis where the racquet moves down the back of the ball

Question 19

What are the four types of spin that ca be applied to different sports

Answer 19

1. Topspin- ball rotating around the transverse axis, with the top spinning in the SAME DIRECTION AS ITS MOTION- forehand tennis

2.backspin- ball rotating around the transverse axis wit the top spinning in the OPPOSITE DIRECTION TO ITS MOTION- backhand in tennis

3. Hook- when the front of the ball spins to the LFET around the longitudinal axis

4.slice- when the ball spins to the RIGHT eg a curled feed in football using the outside of the right foot

Question 20

What i sa Magnus force

Answer 20

The force caused by the pressure differential on either side of a spinning projectile. The force is exerted from a higher to lower pressure.