Mechanics Flashcards
Scalars
Only magnitude
e.g distance, mass, temp, speed
Vector
Magnitude and direction
e.g displacement, velocity, force, acceleration
Moment of a force around a point
Force multiplied by the perpendicular distance from the line of action of the force to the point
Couple
Pair of coplanar forces where the two forces are equal in magnitude but act in opposite directions
Moment of a couple
Multiply one of the forces by the perpendicular distance between the lines of action of the forces
Moment of a couple = force x perp distance between the lines of action of forces
Principle of moments
For an object to be in equilibrium, the sum of anticlockwise moments about a pivot is equal to the sum of clockwise moments
Centre of mass
Point at which an objects mass acts
Speed
Scalar quantity that describes how quickly an object is moving
Velocity
Rate of change of displacement
Acceleration
Rate of change of velocity
Instantaneous velocity
The velocity of an object at a specific point in time. It can be found from a displacement-time graph by drawing a tangent to the graph at the specific time and calculating the gradient
Average velocity
The velocity of an object over a specified time frame. Found by dividing the final displacement by the time taken
Acceleration-time graph
Represent the change in acceleration over time. The area under the graph is change in velocity
Velocity-time graph
Represent the change in velocity over time. The gradient of a velocity time graph is acceleration, and the area under the graph is displacement. Displacement-time graphs show change in displacement over time, so the gradient represents velocity
Free fall
Where an object experiences an acceleration of g
