Topic 2- Forces And Motion Flashcards
What is distance ?
Distance is how far an object moves.
What is displacement ?
Displacement is the distance an object moves in a straight line from a starting point to a finishing point.
What type of quantity is distance ?
scalar quantity
What type of quantity is diplacement ?
Vector quantity
Why is distance a scalar quantity ?
This is because it contains a magnitude (size) but not a direction
Why is displacment a vector quantity ?
This is because it contains a magnitude (size) and direction.
What type of quantity is speed ?
Speed is a scalar quantity.
Scalar quantities only have a magnitude (size).
Scalar quantities, like speed, do not have a direction
What type of quantity is velocity ?
Velocity describes an object’s direction as well as its speed.
Velocity is a vector quantity because it has a magnitude (or size) and a direction.
Fact
To add vectors, draw each vector as an arrow one after the other.
The length of the arrow represents the magnitude (size) of a quantity.
The direction of the arrow represents the direction of the vector quantity.
If an object travels 4 metres forwards then 2 metres backwards, what is the distance travelled? What is the object’s displacement?
The total distance travelled is 4 + 2 = 6 metres. Distance does not depend on direction.
The displacement is 4 - 2 = 2 metres. The second part of the journey is taken in the opposite direction so we take away this part of the journey. The object is only 2 metres from where it was to begin with.
If a car travelling at a velocity of +10m/s suddenly turns around and continues at the same speed, what is its new velocity?
-10m/s
How is an objects speed shown on a distance-time graph
An object’s speed is shown by the gradient (slope) of the distance-time graph
If an object’s speed increases, the object will travel a longer distance in the same amount of time.
What will this do to the gradient ?
The slope (gradient) of the distance-time graph will become steeper
If an object’s speed decreases, then the object will travel a shorter distance in the same amount of time.
What does this do to the gradient ?
The slope (gradient) of the distance-time graph will become less steep.
On a speed-time graph if there is a horizontal line what does this mean ?
The object is moving at a constant speed
On a velocity-time graph if there is a horizontal line what does this mean ?
The object has stopped
The area under a velocity-time graph is equal to what ?
The area under a velocity-time graph is equal to the distance travelled by an object.
To find the area under the graph, what do we do ?
break it down into small shapes and add the areas of the shapes
How do you work out area of a triangle ?
The area of a triangle = 0.5 x base x height.
How do you work out area of a rectangle ?
The area of a rectangle = base x height.
If an object travels at 10 m/s constantly for 1 minute, how far will it have travelled?
600 m
How do you work out average speed ?
The average speed is the total distance travelled divided by the total time taken
What can we use to mesure speed ?
We can measure speed using light gates
Average speed = ? ÷ ?
Average speed = total distance ÷ total time.
It is usually measured in m/s.