Flashcards in Explaining motion Deck (83)

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1

## What does the speed of an object tell us?

### How far it will travel in a certain time

2

## How do you calculate speed?

### Speed (m/s) = distance travelled (m)/time(s)

3

## If the object is not travelling at a constant speed what does distance/time give us?

### The average speed.

4

## How many seconds in a minute?

### 60

5

## How many seconds in an hour?

### 3600

6

## If the question gives time in hours, and you need to calculate speed in m/s, what can you do?

### Convert hours into seconds.

7

## What does average speed over a very short time interval give you?

### A value that is close to instantaneous speed (though it will still be an average over that small time interval)

8

## What is the displacement of an object?

### The distance from the start - so earth travels a long way in a year, but the displacement (seen from the sun) is zero.

9

## Why is displacement a vector?

### It has size (magnitude) and direction.

10

## What is velocity?

### Speed in a certain direction.

11

## Why is velocity a vector?

### It has magnitude and direction.

12

## When plotting a distance time graph, where does time go?

### On the X axis

13

## When plotting a distance time graph, where does distance go?

### On the Y axis.

14

## What does a horizontal line on a distance time graph tell you?

### The object being tracked is not moving.

15

## What is horizontal?

### Parallel to the floor ... the X axis on a graph

16

## What is vertical?

### Sticking straight up into the air... the Y axis on a graph.

17

## On a distance time graph, what is the gradient equal to?

### The speed, but only if you have time on the X axis.

18

## On a distance time graph, what does a curved line show?

### The speed is changing

19

## On a distance time graph what does a steeper line mean?

### The object being tracked is moving faster.

20

## On a distance time graph what would a vertical line mean?

### The object has moved an infinite amount of distance in zero time.

21

## What is a displacement time graph?

### A way of showing a return journey, where displacement goes to 0 when the object returns.

22

## What does the graph going below the X axis mean on a displacement time graph?

### The object went past the starting point and kept going, it is now behind the position that it started at.

23

## What is acceleration?

### The rate at which an object changes velocity

24

## If an object is slowing down, what is it doing?

### Showing negative acceleration. Can be called retardation or deceleration.

25

## What is the unit of acceleration?

### metres per second per second - m/s^2

26

## What is a car doing when going round the corner at a constant speed?

### Accelerating. It is changing direction, this is still acceleration

27

## On a speed-time graph, what goes on the X axis?

### Time

28

## On a speed-time graph, what goes on the Y axis?

### Speed

29

## On a speed time graph, what does a horizontal line mean?

### The object is going at constant speed.

30