Module 3 Statics Flashcards
What is equilibrium?
object has no resultant force/net force is zero, and has no resultant moment (constant velocity)
Newtons’ first law?
an object will continue to move at constant velocity or continue to be at rest unless a resultant force acts on the object
When can the laws of statics be applied ie resultant force = 0N?
when an object is moving at constant velocity or at rest
What does a free body diagram represent?
shows one object with all the forces acting on it
Where do you draw contact forces on a free body diagram?
from points of contact (eg wheels on car on a road)
How do you draw weight in a free body diagram?
from centre of mass, always vertically downwards
What is a closed vector diagram?
a force triangle where resultant forces is zero
How to draw arrows in a closed vector triangle?
in a loop, resultant force is zero
arrows on forces follow on around the loop
When is a closed vector triangle used?
when there are three forces acting on an object in equilibrium
Using the idea of equilibrium, what can we say about horizontal and vertical forces?
both horizontal components add up to zero and vertical components add to zero
If an object is at rest on a slope, usually what are the forces acting on an object?
- weight (vertically down)
- friction (opposite to velocity)
- normal contact force (at right angles to slope)
What are the two components of forces when working with slopes?
along the slope and at right angles to the slope
How would you calculate the component of the weight acting along the slope?
W x sin (angle of slope)
How would you calculate the component of the weight acting at right angles to the slope?
W x cos (angle of slope)
How do you describe the forces acting on an object on a slope?
along the slope or at 90 degrees to the slope
(parallel to slope or perpendicular to slope)
