2.6. Sign Convention

Try these first

1. 1.

   What direction is considered positive for the x-axis?

   Hint

   Think of the direction you normally write.

2. 2.

   Is the positive y-direction upward or downward?

   Hint

   Consider what direction we usually refer to as 'up'.

3. 3.

   What is the positive x-direction?

   • To the left
   • Upwards
   • To the right

   Hint

   Think of navigation on a Cartesian plane.

4. 4.

   Why is it essential to use a sign convention?

   • True
   • False

   Hint

   Consider why clear communication is important.

5. 5.

   A beam has a downward force of 200N and a counter-clockwise moment of 50Nm. Sketch the free body diagram and indicate the forces and moments using the sign convention.

   Hint

   Remember to use arrows to indicate the forces and moments clearly.

6. 6.

   If an engineer misapplies the sign convention in analysis, what steps should they take to correct their calculations?

   Hint

   Think of the importance of double-checking work for accuracy!