Biomechanics: Impulse Flashcards
1
Q
How do we calculate force?
A
- F= MA
( force= mass x acceleration).
2
Q
Define impulse
A
- The length of time a force is applied to an object or the body and relates to a change in momentum that occurs as a consequence.
3
Q
How is impulse calculated?
A
- Force x time
(Basically how long a force is applied).
4
Q
Key fact about impulse
A
- Impulse is equal to a change in momentum.
5
Q
What is a positive impulse?
A
- If an individual or object is accelerated, it is called positive impulse.
6
Q
What is a negative impulse?
A
- If an individual or object is slowed down/ decelerated, it is called negative impulse.
7
Q
When do these impulses happen in sport?
A
- When a force (impulse) is applied in sport over a period of time to help something speed up or slow down.
- Basically more time in contact with something to speed it up or slow it down.
8
Q
Examples of acceleration (increase in velocity/ positive impulse)
A
- Discus spin.
- Drive in cricket.
- Shoulder pass in netball.
- Push pass in hockey.
- Smash in tennis.
9
Q
Examples of deceleration (decrease in velocity/ negative impulse)
A
- Catching a ball in cricket.
- Stopping a hockey ball.
- Landing a somersault in gymnastics.
- Eccentric phase in plyometric training.
10
Q
Impulse and sprinting
A
- Positive impulse is gained through the push phase of the stride.
- Negative impulse is generated by ‘footfall’ where the foot lands to provide a braking action.
11
Q
Look at force time graphs
A
12
Q
Acceleration phase of a 100m sprint
A
- Net impulse is positive.
- Performer is accelerating.
- Sprinter is at the start of the race.
13
Q
Constant phase of a 100m sprint
A
- Net impulse= zero.
- Runner is at a constant velocity; no acceleration or deceleration.
- Sprinter is mid way through the race.
14
Q
Deceleration phase of a 100m sprint
A
- Net impulse is negative.
- Performer is decelerating.
- Sprinter towards the end of the race.
