SP9

Question 1

Define moment

Answer 1

The rotational effect of a force

Question 2

What is a pivot

Answer 2

The central point on which something turns

Question 3

Equation for moment

Answer 3

Nm = FD

Question 4

What is the principle of moments

Answer 4

Sum of clockwise moments = sum of anticlockwise moments

Question 5

When does the principle of moments apply

Answer 5

When the rotational forces are in equilibrium

Question 6

Purpose and function of levers

Answer 6

• Transfer the turning effect as there is a rotation around the pivot
• Decrease force required - they increase distance between pivot and force

Question 7

Purpose and function of gears

Answer 7

• Gears rotate and transfer rotational effect
• Larger gears have a larger distance from pivot point
• Bikes - transfer effect from pedals to back wheel

Question 8

How to adjust to cycling uphill

Answer 8

• Decrease gear = Increase gear size
• Increased gear size = larger distance from pivot
• Large force from cyclist and increased distance from pivot = increased moment

Question 9

Define equilibrium (forces)

Answer 9

All forces are balanced

Question 10

How should you arrange forces on a vector diagram

Answer 10

Tip to tail

Question 11

What is the main difference between contact and non-contact forces

Answer 11

• Contact - objects physically touch
• NContact - objects are not required to touch

Question 12

Name types of non-contact forces

Answer 12

• Gravitational
• Electrostatic
• Magnetic fields

Question 13

Name types of contact forces

Answer 13

• Normal contact forces (reaction forces)
• Friction