Chapter 9 - Constant Acceleration Flashcards
Displacement-Time Graphs
For displacement time-graphs, what does the velocity represent?
✯ Velocity = Change in displacement/ Change in time
How can we find the average velocity, from displacement time graphs?
✯ Average Velocity = Displacement from starting point/ Total time taken
How can we find the average speed, from displacement time graphs?
✯ Average Speed = Total Distance Travelled/ Total time taken
Describe the motion of the ball from the time it was thrown until it reaches its highest point, then after reaching its highest point.
The model of the graph is:
y = -ax^2+bx+c
✯ The velocity of the ball is positive (upwards) and decreases (the ball is decelerating) until it reaches 0 at the highest point.
✯ The velocity of the ball is negative (downwards), and increases (the ball is accelerating) until it hits the ground at the same speed at which it was launched.
What happens when the displacement-time graph is moving like a straight line?
✯ Velocity = 0, as the object is stationary/ at rest.
Velocity Time Graphs
What happens when the velocity-time graph is moving like a straight line?
✯ The velocity remains unchanged over t.
What does the acceleration represent in a velocity time graph?
✯ The gradient of the Velocity-Time Graph.
= Change in Velocity/ Change in Time
What does the area in velocity-time graph represent?
✯ The area between a velocity-time graph and the horizontal axis represents the distance travelled (or displacement)
✯ So distance = Velocity x Time
What happens when a particle changes direction?
✯ The particle has zero velocity.
What happens a particle returns to the origin?
✯ The displacement (s) from the origin is 0.
Name me one modelling assumption when dealing with Vertical Motion…
Air Resistance is neglected (as it affects acceleration).
External forces are neglected.
The weight and spin of the particle is neglected.
Relationship between mass and acceleration?
✯ Mass is inversely proportional to acceleration!
When a particle is moving downwards, what direction must be positive?
✯ Downwards direction
