Topic 10 - Drag

Which statement describes form drag?

• As a body pushes against a fluid, the fluid pushes back against the body.

• As a body moves through a fluid, its surface catches a layer of fluid slowing it down.

• When a body moves along a surface, some fluid is displaced to form a wave.

• When a body moves through a fluid, some fluid attaches to the surface and slows down.

The 1968 Olympic Games were held in Mexico City. Mexico City is at an altitude of around 2200 metres above sea level. Which is the most likely reason for a large number of records being set in short-distance races?

• The oxygen content at altitude is less than it is at sea level.

• The oxygen content at altitude is higher than it is at sea level.

• The air density at altitude is less than it is at sea level.

• The air density at altitude is higher than it is at sea level.

What is drag?

• The force that acts parallel to the interface of two surfaces that are in contact, and opposes their relative motion

• The force or forces acting to oppose the motion of an object through a fluid medium

• The inverse relationship between airflow velocity and air pressure

• The force or forces acting to promote the motion of an object through a fluid medium

Which statement describes surface drag?

• As a body pushes against a fluid, the fluid pushes back against the body.

• As a body moves through a fluid, its surface catches a layer of fluid slowing it down.

• When a body moves along a surface, some fluid is displaced to form a wave.

• When a body moves through a fluid, some fluid attaches to the surface and slows down.

Which statement describes wave drag?

• As a body pushes against a fluid, the fluid pushes back against the body.

• As a body moves through a fluid, its surface catches a layer of fluid slowing it down.

• When a body moves along a surface, some fluid is displaced to form a wave, which cause additional forces.

• When a body moves through a fluid, some fluid attaches to the surface and slows down.

What factor influences a downhill speed skier's form drag?

• Waxed skis

• Length of skis

• Looking downhill

• Body position

What factor influences amount of wave drag for a swimmer?

• avoiding motion at the interface between air and water

• adopting a low profile position on the starting blocks.

• shaving the swimmer’s body to make it smooth.

• wearing hand paddles and fins

Which factor reduces a track cyclists surface drag?

• Tucked body position on the bike

• Sitting behind another cyclist

• Skin tight speed suit

• High pressure slick tyres

A speed skater wants to reduce drag to improve her 500m time. Which factor should her coach ensure she applies when competing?

• Low tucked body position

• Tight speed skin suit

• Stay behind other skaters before overtaking.

• All of the above

Why would a 10m high board diver consider the type of swim suit he wears when diving?

• because he wants to reduce form drag

• because he wants to increase wave drag

• because he wants to reduce surface drag

• because he wants to increase surface drag.