On the move Flashcards
Define Displacement?
Distance in a given direction.
Define Speed?
Change of distance per unit time.
Define Velocity?
Speed in a given direction.
What kind of quantities are speed and distance?
Scalar quantities
What kind of quantities are velocity, displacement and acceleration?
Vector quantities
For objects that travel at constant speed, which equation can you use to calculate speed?
v = s/t speed = distance/time
v = speed (m/s) s = distance (m) t = time (s)
For objects moving at a constant speed, which equation can you use to calculate its speed?
v = 2πr/T speed = circumference of circle / time to move around the circle once
v = speed (m/s) r = radius of circle (m) T = time to move round once (s)
For objects moving at a changing speed, what equation can you use to calculate its average speed?
v = s/t
Average speed = total distance/ total time
v = average speed (m/s)
s = total distance (m)
t =(s)
For objects moving at a changing speed, what equation can you use to calculate its instantaneous speed at a specific point?
v = Δs/Δt
instantaneous speed = distance/time
v = instantaneous speed (m/s) Δs = change in distance in a short time interval (m) Δt = time (s)
On a distance-time graph, what does the height tell you?
The height of a distance-time graph tells you the distance of the object at the time.
On a distance-time graph, what does the gradient tell you?
The gradient of a distance-time graph tells you the speed of the object at that time.
On a distance-time graph, what type of graph line is produced by an object moving at a constant speed?
For an object moving at constant speed, a straight sloping line with a constant gradient is produced.
- For an upwards straight sloping line, the object is moving at constant speed. A steeper line indicates that it is travelling at a higher constant speed. A shallower steep line indicates that it is travelling at a lower constant speed.
- On a distance-time graph, there are no downwards sloping lines (no negative gradient)
On a distance-time graph, what type of graph line is produced by an object moving at a constantly changing speed?
*This is the same for a displacement time graph.
For an object moving at constantly changing speed, a curved line with a changing gradient is produced.
- If the object is increasing in speed (accelerating), an upwards curving line with an increasing gradient is produced.
- If the object is decreasing in speed (deccelerating), a downwards curving line with a decreasing gradient is produced.
How to calculate the instantaneous speed on a distance-time graph for an object that is moving at a constant speed at time t?
*This is the same for a displacement-time graph.
Calculate the gradient of the graph line at time t.
How to calculate the instantaneous speed on a distance-time graph for an object that is moving at a constantly changing speed at time t?
*This is the same for a displacement-time graph.
Draw a tangent to the graph line at time t, and calculating gradient of the tangent.
On a distance-time graph, what type of graph line is produced by an object which is stationary?
*This is the same for a displacement-time graph.
On a distance-time graph, for an object that is stationary, a straight horizontal line (gradient = 0) will be produced.
On a speed-time graph, what does the height tell you?
The height of a speed-time graph tells you the speed of the object at the time.
On a speed-time graph, what does the gradient tell you?
The gradient of a speed-time graph tells you the acceleration of the object at the time.
On a speed-time graph, what type of graph line is produced by an object moving at a constant speed?
On a speed-time graph, for an object that is moving at a constant, a straight horizontal line (gradient = 0) will be produced. This is the same for a velocity-time graph.
On a speed-time graph, what type of graph line is produced by an object moving at a constantly changing speed?
For an object moving at constantly changing speed, a straight sloping line with a constant gradient is produced.
- If the object is increasing in speed (accelerating) at a constant rate, an upwards straight sloping line with a constant gradient is produced.
- If the object is decreasing in speed (deccelerating) at a constant rate, a downwards straight sloping line with a decreasing gradient is produced.
On a speed-time graph, what type of graph line is produced by an object which is stationary?
A straight horizontal line a y = 0
This is the same for a velocity-time graph.
On a speed-time graph, what does the area under the graph represent?
The CHANGE in distance of the object.
On a displacement-time graph, what does the height tell you?
The height of a displacement-time graph tells you the displacement of the object at the time.
`On a displacement-time graph, what does the gradient tell you?
The gradient of a displacement-time graph tells you the velocity of the object at the time.
On a displacement-time graph, what type of graph line is produced by an object moving at a constant velocity?
For an object moving at constant velocity, a straight sloping line with a constant gradient is produced.
- For an upwards straight sloping line, the object is moving at constant velocity away from the start point with a positive gradient (positive velocity)
- For a downwards straight sloping line, the object is moving at a constant velocity returning to the start point with a negative gradient (negative velocity)
Steeper line = the higher its speed.
Positive gradient = first direction
Negative gradient = opposite direction
When the graph line returns to the starting point and continues to move in that direction, it will have a negative displacement.
On a velocity-time graph, what does the height tell you?
The height of a velocity-time graph tells you the velocity of the object at the time.
On a velocity-time graph, what does the gradient tell you?
The gradient of a velocity-time graph tells you the acceleration of the object at the time.