10 minutes maximum! Can you do it in 5?

1. Which one of these is the correct formula for calculating a moment?

• A. moment = force ÷ distance (at right-angles to force)
• B. moment = force x distance (at right-angles to force)
• C. moment = mass x velocity
• D. moment = mass ÷ velocity

2+3. A 5N box is placed on the left-hand side of a light beam as shown:

2. What is the moment produced by the box?

• A. 10 Nm clockwise.
• B. 2.5 Nm clockwise.
• C. 10 Nm anti-clockwise.
• D. 2.5 Nm anti-clockwise.

3. A second box of weight 10 N is added to the beam. Where should it be placed to make the beam balance?

• A. 0.25 m to the right of the pivot.
• B. 1 m to the right of the pivot.
• C. 0.25 m to the left of the pivot.
• D. 1 m to the left of the pivot.

4. A door handle is 0.2 m long and needs a moment of 4 Nm to turn the handle and open the door. What is the minimum force that needs to be applied to the end of the handle to open the door?

1. 0.8 N
2. 0.05 N
3. 8 N
4. 20 N

5&6. This beam has 2 weights suspended from it. However it is not balanced.

5. What is the resultant moment on he beam?

1. 2 N anticlockwise
2. 8 Ncm anticlockwise
3. 2 N clockwise
4. 8 Ncm clockwises

6. To make the beam balance, how far should the 8N weight be to the right of the pivot?

1. 6 cm
2. 9 cm
3. 10 cm
4. 12 cm

7-10. These questions are about a seesaw.

When different children sit on the see-saw they find they have to move to different points to make the see-saw balance.

What are the missing values needed to make the seesaw balance?