Speed + Distance, Displacement, Velocity + Acceleration + Velocity time graphs

Speed equation

Speed = distance/ time

V=s/t

1. Units for acceleration

2. deceleration

1. (m/s²)

2. how fast the velocity is changing when an object slows down.

Typical speed (m/s) for:

Sound, walking, jogging, bike

Sound - 300-360 m/s

Walking - 1.5 m/s

Jogging - 3 m/s

Bike - 6 m/s

Instantaneous speed

The speed of an object at a particular moment in time.

Average speed

The total distance the object travels divided by the total amount of time taken.

Distance time graphs:

What is on the y axis?

distance

Distance time graphs:

What is on the x axis?

time

Distance time graphs:

What does a angled straight line show?

What does a horizontal straight line show?

What does a steeper (higher gradient) line show?

What is the equation for velocity?

movement

stationary

Moving at a fast pace

Distance/ time

Distance time graphs

Scalar meaning

having only magnitude, not direction.

Vector meaning

a quantity having direction as well as magnitude, especially as determining the position of one point in space relative to another.

1. Distance def

2. Displacement def

Distance	How far the object has travelled in metres - scalar
Displacement	distance in a given direction - vector.

How do you calculate the speed in a displacement-time graph?

To calculate the speed you need to divide the distance by the time taken. This is the gradient of the straight line.

Reminder of how to calculate the gradient

gradient = rise/run

Therefore speed is:

speed = distance traveled/ time taken

Speed just tells us how fast something is moving.

Velocity tells us how fast something is moving AND what direction it is moving in.

Speed just tells us how fast something is moving.

Velocity tells us how fast something is moving AND what direction it is moving in.

Def of these key words:

1. Magnitude

2. Scalar

3. Vector

1. Another word for size

2. Just magnitude

3. Direction and magnitude

Acceleration def

 is a measure of how quickly an object changes velocity or 'the rate of change of velocity'.

word equation for acceleration:

acceleration = change in velocity/ time taken

symbol equation for acceleration:

Velocity time graphs:

What goes on the y-axis?

What does negative velocity mean?

What does it look like on the graph?

velocity

going backwards behind your starting point

Going below the x axis

2 possible meanings of negative acceleration

1. slow down - deceleration

2. Going backwards

How Velocity time graphs work:

acceleration

displacement

describing the motion using words

• Calculate the acceleration (this is the gradient of the line),

• The displacement (the area under the line(triangles and rectangles)),

• Describe the motion using words.

How do you find out how far an object has traveled using the velocity-time graph?

Finding the area under the line.