P5 Distance, Displacement, Speed and Velocity (page 207) Flashcards
Distance is what?
Scalar
Displacement is a what?
Vector
What is meant by Distance?
just how far an object has moved. It’s a scaler quantity (p.201) so it doesnt involve direction.
What is meant by Displacement is a vector quantity?
It measures the distance and dirction in a straigh line from an object’s starting point to its finishing point.
e.g. the plane flew 5 metres north. The direction could be relative to a point, e.g. towards the school, or a bearing (a three-didget angle from north, e.g. 035°).
If you walk 5 m north, then 5 m south, what would your displacement be? and what wold the distance travelled by?
0m m but the distance travelled is 10 m
Speed and Velocity both measure what?
how fast you’re going, but speed is a scalar and velocity is a vector.
Explain what speed is?
how fast you’re going (e.g. 30 mph or 20 m/s) with no regard to the direction.
Explain what Velocity is?
Speed in a given direction, e.g. 30 mph north or 20 m/s, 060°
Explain what speed and velocity means?
It means you can have objects travelling at a constant speed with a changing velocity. This happens withn the object is changing direction whilst staying at the same speed.
If an object is moving in a circle at a constant speed and has a constantly changing velocity, what do this mean?
the direction is always changing (e.g. a car going round a roundabout)
If you want to measure the speed of an object that’s moving with a constant speed, how do you do this?
you should time how long it takes the object to travel a certain distance, e.g. using a ruler and a stopwatch. You can then calculate the objects speed from your measurements using this formula:
s = vt
distance travelled (m) = speed (m/s) x time (s)
Objects rarely travel at a constant speed, give some examples and explain why?
e.g. when you walk, run or travel in a car, your speed is always changing.
for these cases, the formular gives the average (mean) speed during that time.
Whilst every person, train or car etc is different there is usually a typical speed that each object travels at (remember these typical speeds for everyday objects), what are the speeds for the following:
A person walking
A person running
A person cycling
A car
A train
A plane
A person walking 1.5 m/s
A person running 3 m/s
A person cycling 6 m/x
A car 25 m/s
A train 30 m/s
A plane 250 m/s
Lots of different things can affect the speed something travels at, give some examples?
the speed at which a person ccan walk, run or cycle depends on their fitness, there age, the distance travelled and the terrain (what kind of land they’re moving over, e.g. roads, fields) as well as many other factors.
Its not only the speed of objects that varies, what else can varie?
the seed of sound (330 m/s in air) changes depending on what the sound waves are travelling through, and the speed of wind is affected by many factors.