Forces Flashcards
What is the difference between contact and body forces?
Contact forces are applied by direct contact
Body forces are applied over fields
What are concurrent forces?
Forces which act at the same point of application
Due to the collinearity of forces, any intersection of lines of forces counts as a shared point of application
What is the Sine Rule?
a/sinA=b/sinB=c/sinC
What is the Cosine Rule?
a^2=b^2+c^2-2bc*cosA
What form must the final angle answer to a question be in?
Angle to the horizontal
How can you check a resultant force question visually?
Draw each force to scale, tip to tail, and see if the result (roughly) matches the calculated answer
What is the sense of a moment?
The rotational direction
If a moment is plotted on the positive z-axis, what is meant?
The moment has an anticlockwise direction
What happens if you multiply a unit vector by itself?
The result is zero
What is the unique property of a moment couple?
A rotation is created with no translation
What is true of tension in a cable?
It always acts away from the body it is acting on
What is the maximum number of unknowns that can be solved?
3
What must you remember if the thickness of a beam is given?
Both x and y directions have the capability of creating moments
