The Magnus Effect

Question 1

the magnus effect

Answer 1

• The term used to describe the effect of rotation on an objects path as it moves through a fluid
  
  • It applies Bernoulli’s to explain the effect spin has on the trajectory of the object
  • When a ball is struck with an eccentric force (off-centre), there is both linear and angluar rotation
    The rotating ball interacts with the oncoming air

Question 2

types of spin

Answer 2

top spin
back spin
side spin

Question 3

top spin

Answer 3

It causes the ball to dip and travel shorter in flight which allows for greater margin of error when hitting over a net
The ball can be hit with more velocity impacting the opponents time to return the shot

Question 4

back spin

Answer 4

This causes the ball to rise higher in the air and fly further
This applies to events where distances needs to be maximised
It can be used to keep the ball in play if the player needs to stay in the rally as it gives players more time

Question 5

how does a ball spin

Answer 5

given ball is travelling right and airflow is coming from right (0 <-) for topspin

• on top of the ball, boundary layer of air is travelling in the opposite direction to oncoming airflow, resulting in a LV HP
  ○ Low velocity results in an area of high pressure, meaning the ball wants to go to low pressure

on the bottom of the ball, boundary layer of air is travelling in the same direction as the oncoming airflow resulting in an increase in HV LP
High velocity results in an area of low pressure

since HV is at bottom, ball spins forwards as LV is on top.

for backspin opposite is applied
side spin is same just perpendicular ykwim

Question 6

affect spin has on flight path

Answer 6

top spin - drops ball shorter and faster
no spin - normal
back spin - floats ball for longer and higher

Question 7

affect spin has on bounce

Answer 7

top spin - balls bounces travel further
no spin - normal
backspin - ball bounces travel less far and come to a stop quicker (x(t) wise)

Question 8

applications of spin

Answer 8

• Golf
  ○ Uses side spin to work around corners
  ○ Backspin is used to allow players to attack the green
  
  • Tennis
    ○ Topspin is used to hit the ball with greater force and reduces risk as the ball will dip during its flight
  • Football
    ○ Backspin is used to kick the ball greater distances
    ○ Sidespin is used to get around walls for free kicks
  • Volleyball
    ○ Topspin is used in serves to hit harder and have the ball drop
    No spin serves means the ball travels erratically through the air