Impulse & Momentum
Define impulse.
Impulse = Force × Time (product of force and the time it is applied).
Define angular momentum.
Angular momentum = Moment of Inertia × Angular Velocity.
Name one type of drag.
Surface drag, Form drag, or Wave drag.
What is Bernoulli’s principle?
Faster fluid flow = lower pressure; slower fluid flow = higher pressure.
Define balance.
The ability to maintain control of body position (equilibrium).
What is the impulse–momentum relationship?
Impulse causes a change in momentum (Impulse = ΔMomentum).
What is moment of inertia?
A body’s resistance to rotation, determined by mass and how far mass is distributed from the axis of rotation.
Define form drag.
Resistance caused by turbulence and pressure differences around an object’s shape.
What is lift force?
Upward force generated by pressure differences caused by airflow (explained by Bernoulli’s principle).
Explain base of support.
The area beneath an athlete that supports them; wider BOS = more stability.
Why do high jumpers land on a soft mat?
The mat increases contact time → reduces force on the body → decreases injury risk.
Explain why a diver spins faster when tucking.
Tucking reduces moment of inertia → angular velocity increases → conservation of angular momentum keeps total momentum the same.
Explain boundary layer separation.
When airflow detaches from the object’s surface, creating turbulence and increased drag. E.g. smooth vs dimpled golf ball.
Define Magnus Effect.
The curve of a spinning ball due to pressure differences from asymmetric airflow.
Difference between simultaneous and sequential movement.
Simultaneous: body parts move at same time for force (e.g. shot put). Sequential: large → small segments in order for speed (e.g. tennis serve).
Explain how a sprinter generates momentum from the blocks.
They apply a large force over a short time against the blocks, creating a large impulse → increases forward momentum → faster start.
Give a sport example of torque increasing performance.
A javelin thrower uses a long arm to create a longer moment arm, producing more torque → greater release speed.
Give one strategy athletes use to reduce drag.
Streamlined body position in swimming, wearing tight clothing in cycling, tucking posture in ski jumping.
Explain why topspin helps a tennis shot.
Topspin creates higher pressure above, lower below → downward Magnus force makes ball dip faster → allows harder shots that still land in.
Why does a larger ROM increase speed but reduce accuracy?
Greater ROM = more distance for acceleration = more speed, but harder to control movement so less accurate.
Explain the impulse–momentum relationship in tackling.
The tackler applies force over time to stop the opponent’s momentum. A larger impulse is required to stop a player with greater mass or velocity.
Explain conservation of angular momentum with an example.
In mid-air, a gymnast’s angular momentum is conserved (no external torque). Changing shape alters MOI → angular velocity adjusts (arms in = spin faster).
Explain how laminar vs turbulent flow affects performance.
Laminar = smooth flow, less drag; Turbulent = irregular, more drag. Athletes aim to delay turbulence for efficiency (e.g. dimples on golf balls).
Compare topspin and backspin using Bernoulli’s principle.
Topspin = pressure high on top, low underneath → ball dips downward. Backspin = pressure low on top, high underneath → ball lifts, stays in air longer.
Explain segmental interaction in a tennis serve.
Energy transfers from legs → hips → trunk → shoulder → arm → wrist. Each segment adds to velocity, maximising racket head speed.