Projectile motion

Question 1

Projectile motion

Answer 1

-Projectile motion is the movement of a body in the air following a curved path

Question 2

Factors affecting horizontal distance travelled by projectile

Answer 2

-Speed of release= larger change in momentum and acceleration if larger force applied
-Angle of release- optimum angle of release is 45 degrees for maximal horizontal distance
-Height of release= if height of release= to landing height then 45 degress is the optimum
-If height of release is above the landing height, then the optimum angle of release is less than 45 degrees
-If the height of release is lower than the landing height, then the optimum angle of release is more than 45 degrees

Question 3

Parabolic vs non parabolic flight path

Answer 3

-Parabolic flight path is symetrical, and occurs when weight is the dominant force, so the object is not affected much by air resistance
-Non parabolic flight pathis asymmetrical, air resistance is the dominant force over weight e.g badminton shuttlecock

Question 4

Bernouillis principle

Answer 4

Bernoullis principle states that the higher the velocity of air flow, the lower the surrounding pressure
-This causes a lift force to be created

Question 5

Aerofoil shape

Answer 5

Aerofoil shape is when an object has a curved upper surface and a flat lower surface
-This causes low pressure at the top of the object and low pressure at the bottom of the object
-All fluid moves from high to low pressure, generating a lift force

Question 6

reverse aerofoil (f1)

Answer 6

-The higher the velocity of airflow the higher the surrounding pressure
-F1 cars have a reverse aerofoil spoiler
-the air velocity is higher below the spoiler, causing the pressure below the spoiler to be lower
-The air velocity above the spoiler is lower, meaning the pressure above the spoiler is higher
-This movement from high to low pressure creates the downwards force that allows the car to stick to the track

Question 7

Magnus force

Answer 7

Magnus force is the additional force created by the pressure gradients on opposing sides of an object moving in the air

Question 8

Topspin

Answer 8

-Topspin is created by applying an eccentric force to above the centre of mass
-The upper surface rotates towards oncoming air flow, decreasing velocity and increasing pressure
-The bottom surface however, rotates away from oncoming air flow, increasing velocity and decreasing pressure
-This partial pressure causes a downward Magnus force, creating a non-parabolic flight path

Question 9

Backspin

Answer 9

-Bacskpin occurs when an eccentric force is applied to outside the centre of mass
-The upper surface of the ball rotates in the same direction as oncoming air flow, decreasing pressure and increasing velocity
-The lower surface of the ball rotates towards oncoming air flow, decreasing velocity and increasing pressure
-This cause an upwards Magnus force, causing a parabolic flight path and the ball to travel further

Question 10

Sidespin hook

Answer 10

-Sidespin hook occurs when an eccentric force is applied to the right of the centre of mass
-The left side of the ball is rotating in the same direction as oncoming air resistance, therefore it has low pressure and high velocity
-The right surface of the ball is opposing the direction of oncoming air resistance, so has high pressure and decreases velocity
-This pressure difference causes the magnus force to shift left, moving the ball to the left

Question 11

Sidespin slice

Answer 11

opposite to side spin hook (goes right)