5.4 Moments, levers and gears

Question 1

What is a moment? (1)

Answer 1

The turning effect of a force.

Question 2

What is the equation to calculate the size of the moment of a force? (1)

Answer 2

Moment (Nm) = force (N) x [perpendicular] distance [from the pivot to the force’s line of action] (m)

Question 3

What can be said about the moments acting in an object when an object is balanced/in equilibrium? (1)

Answer 3

The clockwise moment is equal to the anti-clockwise moment.

Question 4

What parts make up a lever system? (3)

Answer 4

• Load
• Effort
• Pivot

Question 5

How can a lever be used as a force multiplier? (3)

Answer 5

• If the distance between the force applied and the pivot is greater than the distance between the load and the pivot,
• the force applied on the load is greater than the effort force
• because the moment on the load and effort must be the same.

Question 6

What is an example of when a gear may be used as a force multiplier? (1)

Answer 6

Wrench - long handle means force applied by user is greater.

Question 7

What determines a gear’s moment? (1)

Answer 7

The size of the wheel

Question 8

What determines a gear’s moment? (1)

Answer 8

The size of the wheel

Question 9

Describe the speed and moment of a larger gear driven by a smaller gear. (2)

Answer 9

• The larger gear will move at a slower pace
• The larger gear will produce a larger moment.

Question 10

Describe the speed and moment of a smaller gear driven by a larger gear. (2)

Answer 10

• The smaller gear will turn at a faster rate
• The moment produced will be smaller