Cards In This Deck

• $\text{When calculating the resultant moment of a system of forces, how do you handle the direction of rotation?}$
  $\text{Choose one direction (e.g., clockwise) as positive and the other (anticlockwise) as negative, then sum them.}$
• $\text{What is the formula for the moment of a force }F\text{ about a point }P\text{ when the distance }d\text{ makes an angle }\theta \text{ with the line of action of the force?}$
  $Moment=|F|\times d\sin \theta$
• $$\begin{gathered} \text{True or False? } \\ \text{To calculate the moment of a force }F\text{ applied at a point }P\text{, you simply multiply the magnitude of the force by the straight-line distance from the pivot to }P\text{.} \end{gathered}$$
  $$\begin{gathered} \text{❌ False} \\ \text{✅ Correct: You must multiply the force by the perpendicular distance from the pivot to the line of action of the force.} \end{gathered}$$
• $$\begin{gathered} \text{True or False? } \\ \text{If the resultant moment on a body is zero, the body must be in equilibrium.} \end{gathered}$$
  $$\begin{gathered} \text{❌ False} \\ \text{✅ Correct: Zero resultant moment only prevents rotation. For full equilibrium, the resultant force must ALSO be zero to prevent translation.} \end{gathered}$$
• $\text{In a rigid body equilibrium problem with two unknown vertical reaction forces at supports A and B, which point should you choose to take moments about first?}$
  $\text{Take moments about either point A or point B.}$
• $\text{A horizontal rod supported at points C and D is ’on the point of tilting about C’. What is the immediate mathematical deduction you should make?}$
  $\text{Set the reaction force at the other support (D) to zero (}{R}_D=0\text{).}$
• $$\begin{gathered} \text{True or False? } \\ \text{When a question states a rod is ’uniform’, it means the rod has negligible thickness.} \end{gathered}$$
  $$\begin{gathered} \text{❌ False} \\ \text{✅ Correct: ’Uniform’ means the mass is evenly distributed, so the weight acts exactly at the geometric midpoint.} \end{gathered}$$