7.1 Speed and velocity Flashcards
What is displacement
Distance in a given direction
What is speed
Change of distance per unit time
What is velocity
Change of displacement per unit time
Speed in a given direction
An object moving at a constant speed travels…
…equal distances in equal times
Equation: For an object which travels distance in time at a constant speed
v=s/t
Equation: For an object moving at constant speed on a circle of radius r, its speed
v= 2πr/t
What are the two types of speed cameras
One measures the speed of a vehicle as it passes the camera
The other is linked to a second speed camera and computer which works out the average speed of the vehicle between the two cameras
Equation: For an object moving at changing speed that travels a distance s in time t
Average speed = s/t
Equation linking instantaneous speed, distance and a short time interval
v=Δs/Δt
What does Δ show
Change in something
What does the distance time graph of an object moving at constant speed look like
A straight line with constant gradient
What does the gradient of a distance time graph show
The speed of the object
What does the distance time graph of an object moving at changing speed look like
Curved, the gradient changes
How to find the gradient of a curved line at any point
Draw a tangent and find the gradient of that tangent
An object moving at constant velocity…
…moves at the same speed without changing its direction of motion
