Mechanics Flashcards
What is a scalar?
A physical quantity which has magnitude only
Simple examples of scalar quantities are…
Length
Mass
Time
Temperature
What is a vector?
A physical quantity which has both magnitude and direction
Resultant?
Single vector which has the same effect as all the component vectors
Maximum resultant?
•When two vectors act in the same direction
•Angle between them is 0
—Resultant is the sum of the magnitudes of the two vectors
Minimum resultant
- When two vectors act in opposite direction
- Angle between them is 180
- Resultant is therefore the difference of the magnitudes of the vectors
How is position measured?
Relative to a reference point
Is position a vector or a scalar and why?
It is a vector since it has magnitude and direction in relation to the reference point
What is the si unit for position
Metre (m)
What is distance?
The length of the path taken
Distance;scalar or vector?
Scalar
Displacement?
A body’s change of position
Why is displacement a vector?
•One must know the distance from the reference point and the new position as well as the direction in which the body has moved
Speed?
Rate of change of distance moved
Speed;vector or scalar?
A scalar
What is instantaneous speed?
The speed at a particular moment
Velocity?
The rate of change of position
Is velocity a vector or scalar
Vector
Instantaneous velocity?
Velocity at a particular moment
•Magnitude is equal to instantaneous speed but this also contains the object is moving at that instant
Acceleration?
Rate of change of velocity
Acceleration;vector or scalar?
Vector
What does the gradient of a position vs time graph tell uss?
The velocity
Why should the graph be a straight line for the position vs time?
Because the velocity is constant and gradient must be constant
What gives the gradient at a particular point on a increasing velocity position vs time graph
The gradient of a tangent drawn
What does the gradient of a tangent drawn give?
The instantaneous velocity at that point
What does the gradient of a velocity vs time graph give?
The acceleration of a moving object
What does the area under the velocity vs time graph give?
Displacement
What are equations of motion for?
Bodies moving at a constant acceleration and in a straight line
What is delta x
Displacement
