2.1 and 2.3 Moments/Balance

Question 1

Calculation for the size of a moment?

Answer 1

M=f x d

Where m is the moment in Nm
F is the force in N
D is the perpendicular distance from the line of action of the force to the pivot in m

Question 2

Name 2 ways to increase the moment.

Answer 2

• increase the force

* increase the distance to the pivot

Question 3

Why is it easier to undo a wheel nut by pushing on a longer spanner than a shorter spanner?

Answer 3

The distance between the line of action and the pivot increases so we don’t have to use a big force so it is easier for us

Question 4

What is the load?

Answer 4

The force we are trying to move

Question 5

What is the effort?

Answer 5

The force applied to the lever to move the load

Question 6

How does a lever make moments easier?

Answer 6

A lever acts as a force multiplier so the effort we apply can be much less than the load

Question 7

A door opens when you apply a force of 20N at right angles to it, 0.6m from the hinge. What is the moment of the force about the hinge?

Answer 7

12Nm

Question 8

What is a moment?

Answer 8

The turning effect of a force

Question 9

What is a pivot?

Answer 9

Point of turn in a moment

Question 10

What does E(clockwise) = E(anti-clockwise) mean?

Answer 10

In equilibrium, the clockwise moments equal the anti clockwise moments so the forces equal each other

Question 11

If someone sits in the centre of a seesaw, why is the moment about the pivot zero?

Answer 11

Because their perpendicular distance to the pivot is zero

Question 12

Person A sits 2m away from the centre of a seesaw, person B weighs twice as much so where should they sit to balance the seesaw?

Answer 12

1m away from the centre of the seesaw

Question 13

How to work out the resultant moment:

Answer 13

1. Add up all clockwise moments
2. Add up all anti-clockwise moments
3. Subtract the smaller total from the bigger total
4. The number left is the resultant moment in the direction of the bigger total