Module 3 - Forces and motion (Kinematics) Flashcards
Motion: Kinematics
What is meant by the term displacement
The direct distance between an objects starting and finishing position, and itss directon of travel
What is meant by the term instantaneous speed
A measure of the speed of an object over a very short interval of time.
How is instantaneous speed calculated from a distance time graph
- A tangent is drawn about the instant of time
- The gradient of the tangent is determined which represents the instantaneous speed
What is meant by the term average speed
A measure of the total distance travelled over a given time.
How is the average speed of an object determined from a distance time graph
The gradient of the straight line or between the initial and the final point is calculated to determine the average speed
What is a limiatation of finding the average speed in a practical sense and give an example
It does not represent the variation in speed of the object.
(E.G.) A cas average speed may not exceed the average speed limit evemn if it exceeds the limit in one part of the journey.
What is meant by the term acceleration
The rate of change of velocity
What is the equation that links to the definition of acceleration
a = v-u/t
What is meant by the term velocity
The displacement travelled by an object in a given time
What is the equation that links to the definition of velocity
v = s / t
What is the unit of velocity
ms -1
What is the unit of acceleration
ms -2
What does the gradient of an s/t graph represent
The velocity
What does an negative displacement represent on an s/t graph
The motion of the object is in the opposite direction
What does the gradient of a v/t graph represent
The acceleration
What does the area under the graph of a v/t graph represent
The displacement
What does a straight horizontal line represent on a v/t graph, and does this change if it is in the 1st or 4th quadrant
1st Quadrant: Constant velocity
4th Quadrant: Constant velocity in the opposite direction
What does a a straight line with a positive gradient represent on a v/t graph, and does this change if it is in the 1st or 4th quadrant
1st Quadrant: Constant Acceleration
4th Quadrant: Constant Deceleration ( due to the line approaching a lower value so even though a positive gradient because it is in the opposite quadrant it is deceleration).
What does a straight line with a negative gradient represent on a vt graph, and does this change if it is in the 1st or 4th quadrant
1st Quadrant: Constant Deceleration
4th Quadrant: Constant Acceleration in the negative direction
