Kinematics Flashcards
Is distance a scalar or vector quantity?
Scalar.
Is displacement a scalar or vector quantity?
Vector.
When a person throws a ball up in the air is the displacement positive or negative?
Positive displacement upwards.
Why is that positive displacement is upwards and negative displacement is downwards?
Because displacement is a vector quantity.
If a person completed a circular walk that was 20km in 5hrs what would their displacement and distance be?
Displacement = 0km Distance = 20km
What would their average speed and velocity be for the 20km circular walk in 5hrs?
Average:
Speed = 20/5
= 4kmhr^-1
Velocity = 0/5
= 0kmhr^-1Define speed.
The rate of change of distance with respect to time.
Define displacement.
The shortest distance between two points on the line of travel independent of path.
Define velocity.
The rate of change of displacement.
Define Instantaneous speed.
The rate of change of distance at a given instant.
Define acceleration.
The rate of change of velcoity per unit time.
What is the formula to calcuate acceleration?
v-u/t where v = final velcoty, u = initital velocity and t = time.
Give two examples when is an object accelerating.
1) When it’s speed is increasing.
2) When it is changing direction.
Give an example when an object is deceerating.
When it’s speed is decreasing.
Define rate of change.
Change in a quanitity relative to another quanitity, usually time.
What does the gradient of a distance-time graph represent?
The velocity of an object at a specific time.
What does the area under a speed-time graph represent?
The distance travelled in that time at that speed.
What deos the gradient of a speed-time graph represnt?
The magnitude of the acceleration.
Define average speed?
The total distance travelled divided by the time taken to travel that distance.
What does the gradient of a displacement-time graph represent?
The velocity.
What does the area under a velocity-time graph represent?
The displacement.
What does the gradient of a velocity-time graph represent?
The acceleration.
What does a negative gradient on a velocity-time graph represent?
The object is decelerating.
What does a positive gradient on a velocity-time graph represent?
The velocity of an object is increasing.
Sketch a displacement-time graph and velocity-time graph for displacement zero.
Look at notes!
Sketch a s/t, v/t and a/t graph to represent a falling object.
Look at notes!
Define average velocity.
The total displacement divided by the time taken to achieve that displacement.
Define uniform motion.
Motion with no change in velocity, i.e zero acceleration.
What does a straight line on a displacement-time graph represent?
Uniform velocity.
How would you calculate the instantaneous velocity on a displacement-time graph?
Draw a tangent to the point and calculate the gradient of the tangent.
What does a negative gradient represent?
Motion in the opposite direction.
