speed Flashcards
what is the formula for speed?
average speed=distance divided by time
why do we write average speed?
because in a car it is not a constant speed
what is the speed of a car at a certain point in time called?
instantaneous speed
what is the equation for distance travelled?
average speed x time
what is speed a measure of?
how fast an object is moving
how does a speed camera work?
as a speeding car passes it takes a photo
a second photograph is taken 0.5 seconds later. There are white lines painted on the road at distances of 1.5m apart. They show how far the car travels in 0.5 seconds
how are speed cameras set up?
two cameras are placed a measured distance apart (1km)
as a car passes each camera its number plate is recorded
the two images of the same number plate are paired up
what does the picture contain?
a date and time stamp so a computer can then work out the cars average speed between the cameras
what is the equation for average speed?
distance travelled divided by time taken
what is speed measured in?
m/s or km/h
how do you change km/h to m/s?
multiply by 1000 and divide by 3600
how do you change m/s to km/h?
divide by 1000 and times by 3600
what does a distance-time graph show?
how the distance moved by an object changes with time.
what gradient does a graph show if the distance increases and time increases?
a positive gradient
what gradient does a graph show if the distance decreases as time increases?
negative gradient
