Friction and AR

Question 1

What 4 factors affect friction?

Answer 1

Roughness of ground
Roughness of contact surface
Temperature
Size of normal reaction

Question 2

Roughness of ground affecting friction - example:

Answer 2

Athlete runs on rubber tracks to increase friction

Question 3

Roughness of contact surface affecting friction - example:

Answer 3

Athlete runs with spikes to increase friction

Question 4

Temperature affecting friction - example:

Answer 4

F1 drivers warm up tyres in warm up lap to create more friction

Question 5

Size of normal reaction affecting friction - example:

Answer 5

Shot putter have high mass -> inc reaction and friction to prevent over rotation

Question 6

What 4 factors affect AR?

Answer 6

Velocity
Shape
FCSA
Smoothness of surface

Question 7

Velocity affecting AR - example

Answer 7

Cyclist at higher velocity has more AR to deal with

Question 8

Shape affecting AR - example

Answer 8

Tear drop helmets for cyclists to minimise AR

Question 9

FCSA affecting AR - example

Answer 9

Skiers crouch down to reduce AR

Question 10

Smoothness of surface affecting AR - example

Answer 10

Lycra suits to reduce Ar for runners/cyclists