SP9 Flashcards
Forces and their effects (13 cards)
1
Q
Define moment
A
The rotational effect of a force
2
Q
What is a pivot
A
The central point on which something turns
3
Q
Equation for moment
A
Nm = FD
4
Q
What is the principle of moments
A
Sum of clockwise moments = sum of anticlockwise moments
5
Q
When does the principle of moments apply
A
When the rotational forces are in equilibrium
6
Q
Purpose and function of levers
A
- Transfer the turning effect as there is a rotation around the pivot
- Decrease force required - they increase distance between pivot and force
7
Q
Purpose and function of gears
A
- Gears rotate and transfer rotational effect
- Larger gears have a larger distance from pivot point
- Bikes - transfer effect from pedals to back wheel
8
Q
How to adjust to cycling uphill
A
- Decrease gear = Increase gear size
- Increased gear size = larger distance from pivot
- Large force from cyclist and increased distance from pivot = increased moment
9
Q
Define equilibrium (forces)
A
All forces are balanced
10
Q
How should you arrange forces on a vector diagram
A
Tip to tail
11
Q
What is the main difference between contact and non-contact forces
A
- Contact - objects physically touch
- NContact - objects are not required to touch
12
Q
Name types of non-contact forces
A
- Gravitational
- Electrostatic
- Magnetic fields
13
Q
Name types of contact forces
A
- Normal contact forces (reaction forces)
- Friction
