Applying forces in Sport

Question 1

What are vertical forces also known as?

Answer 1

Vertical components

Question 2

What are horizontal forces also known as?

Answer 2

Horizontal components

Question 3

What are the vertical components?

Answer 3

Weight (W) (downwards)
Ground reaction force (GRF) (upwards)

Question 4

What are the horizontal components?

Answer 4

Air resistance (AR) (drag)
Friction (F)

Question 5

What are the paired forces (Newtons 3rd law)?

Answer 5

Action
Reaction

Question 6

What are balanced forces?

Answer 6

Occur when two or more forces are in operation that are equal in size but opposite in direction
NET FORCE IS ZERO

Question 7

What are unbalanced forces?

Answer 7

Occur when a force is acting in one direction is larger than the one acting in the other direction
NET FORCE IS POSITIVE OR NEGATIVE

Question 8

What are resultant forces?

Answer 8

These are the outcome of two forces meeting

Question 9

What are the three resultant forces?

Answer 9

Zero = balanced
Positive = acceleration
Negative = deceleration

Question 10

What does friction oppose?

Answer 10

Friction acts in opposition to motion

Question 11

Is friction bad for sport?

Answer 11

No in fact friction is massively important, without friction everybody would be slipping and sliding all over the place
- Spikes, studs, tires etc. increase friction for performers

Question 12

What are the 6 tips of free body diagrams?

Answer 12

1. The length of the arrow reflects the size of the force
2. Draw a direction of motion arrow
3. Add vertical forces - W and GRF
   - W = GRF (balanced force - subject will not accelerate upwards)
   - GRF > W (unbalanced force - subject will accelerate upwards)
4. Add horizontal forces - F and AR
   - F = AR (balanced force - net force is zero ; constant)
   - F > AR (unbalanced force - subject is accelerating)
   - F < AR (unbalanced force - subject is decelerating)
5. Add paired forces - action force/reaction force
6. Mention resultant forces (acceleration/deceleration/constant)
7. The weight force is drawn from the centre of mass (belly button)
8. GRF starts from where two bodies are in contact with another
9. Friction force is drawn where two bodies are in contact - usually in same direction as motion
10. Air resistance is drawn from centre of mass and opposes direction of the body