P9 Motion Flashcards
What does the gradient of a line on distance-time graph represent?
Speed
State the equation linking distance, speed and time
distance = speed x time
distance (m), speed (m/s), time (s)
How to calculate speed for an object moving at constant speed
speed = distance / time
speed (m/s), distance (m), time (s)
Why can an object travelling at a constant speed in a circle not have a constant velocity?
- Speed is a scalar quantity
- Velocity is a vector quantity which means it can only be constant if the direction is constant
- In circular motion, the direction is constantly changing
- So its velocity is not constant even if its speed is constant
How to calculate acceleration
acceleration = change in velocity / time taken for change
acceleration (m/s²), change in velocity (m/s), time (s)
What is velocity?
Speed in a given direction
How can distance travelled by an object be calculated from a velocity-time graph?
Distance travelled is equal to the area under the graph
What is acceleration?
The rate of change of velocity
What is deceleration?
The change of velocity per second when an object slows down
How can acceleration of an object be calculated from a velocity-time graph?
Acceleration is equal to the gradient of the line