Describe the recommended relative contribution of macronutrients in a healthy balanced diet.

Using an example, discuss the effect of experience and memory on selective attention.

Outline how the Bernoulli principle affects a golf ball in flight.

Apply Newton’s second law of motion to the distance travelled by a golf ball after being struck.

carbohydrates are primary energy source «40–70%» ✔

carbohydrates provide 4 calories per gram / 1760 kJ per 100 grams ✔
proteins contribute a smaller amount «10–30%» ✔

proteins provide 4 calories per gram / 1720 kJ per 100 grams ✔
lipids make up a relatively small amount of intake «10–30%» ✔

fats provide 9 calories per gram / 4000 kJ per 100 grams ✔
recommendations vary by country / age / gender / height / weight / RMR / activity level ✔

calorie intake should be 2000–3000 for males and 1600–2400 females ✔

there is much contention about recommended ranges ✔

Accept other reasonable recommendations.

[5 max]

Experience:

more experienced athletes can better use their long-term memory to improve their selective attention ✔

experienced athletes selectively attend to stimuli quicker than less experienced athletes ✔

selective attention can be improved through over-learning ✔

more experienced athletes better filter stimuli into relevant and irrelevant «noise» ✔

Memory:

the apparent limited capacity of the short-term memory indicates that there is some form of selective attention to prioritise stimuli ✔

more long-term memories provide a greater source to draw from for selective attention ✔

selective attention operates in the short-term sensory store ✔

only relevant information is passed to the short-term memory ✔

Long-term memory will enable a person to attend quickly to the correct stimuli in future situations ✔

Award [4 max] for experience or memory

Award [5 max] if there is no link to a sporting example

[6 max]

the Bernoulli principle explains how relative air pressure «from backspin» around a golf ball means that it experiences a lift force and travels further through the air ✔

as a golf ball travels with backspin, it experiences higher air pressure on the bottom of the ball and lower air pressure on the top of the ball ✔

the ball/object is attracted to the area of lower air pressure, which is above the ball and therefore experiences lift ✔

the lift force is perpendicular to the direction of the airflow ✔

the faster the ball travels / spins, the greater the differences in relative air pressure and therefore the greater the lift force ✔

the dimples on the golf ball encourage small turbulent air, which protects the ball against drag force ✔

a ball struck off «laterally» centre will spin in the air, therefore creating lower relative air pressure on one side and generating curve ✔

Accept annotated diagram to outline the principles.

[5 max]

the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, and inversely proportional to the mass of the object
OR
F = ma ✔

the ball will travel in the same direction as the direction of the net force applied to the ball ✔

when the club contacts the ball, the change in momentum of the club is transferred to the ball/conservation of momentum ✔

the greater the change in momentum of the ball, the longer distance the ball will travel
OR
the greater the impulse applied to the ball, the longer distance the ball will travel ✔

larger clubs /club with greater mass will generate a greater force and therefore propel the ball further
OR
a lighter golf ball will accelerate faster when struck by the golf club ✔

Accept annotated diagrams for suitable mark points.

[4 max]

Most knew which macronutrients were important and gained 3 or 4 marks. In general, appreciation of the differences for different populations or the overall caloric intake was not discussed.

Most gained 3 marks for discussing the effect of experience and memory on selective attention with relevant sporting examples. However, few linked short- and long-term memory to selective attention. The influence of experience was generally answered better.

This was poorly understood by many candidates. Some only stated that it involved air pressure others said it was about gravity stopping the ball. An annotated diagram could have been used to support their explanations.

Few gained full marks but many understood ‘F=ma’ and the relationship between how hard the ball was hit and the distance the ball travelled.