# Calculating%20Speed%20from%20a%20Distance-Time%20Graph - PowerPoint PPT Presentation

View by Category
Title:

## Calculating%20Speed%20from%20a%20Distance-Time%20Graph

Description:

### Draw the velocity vectors for the following: (a) A train travelling at 50 m/s due East (b) A car travelling at 10 m/s due South (c) A marathon runner at 2 m/s due ... – PowerPoint PPT presentation

Number of Views:268
Avg rating:3.0/5.0
Slides: 9
Provided by: MOv7
Category:
Tags:
Transcript and Presenter's Notes

Title: Calculating%20Speed%20from%20a%20Distance-Time%20Graph

1
Calculating Speed from a Distance-Time Graph
Average Speed Distance Moved / Time taken
Calculate the average speed for each of the
section 1 - 4.
2
Difference between Speed and Velocity
Speed is a vector quantity. It only has a size.
It has no direction
For example 5 m/s or 100m/s
Velocity has direction and magnitude. For
example a velocity of 5m/s due North or 30 m/s
due East
Velocity can be negative or positive. The sign
of the velocity will indicate the direction of
the velocity
3
Representing Velocity
Positive direction
5 m/s
This car is travelling at a velocity of 5m/s
due West
This car is travelling at 2 m/s due South
OK....they have no drivers...
4
Representing Velocity
Velocity is represented by a VECTOR ARROW The
direction of the arrow shows the direction of the
velocity The length of the arrow represents the
size of the velocity
Now try this Draw the velocity vectors for the
following (a) A train travelling at 50 m/s due
East (b) A car travelling at 10 m/s due
South (c) A marathon runner at 2 m/s due West.
5
Velocity-time graphs
A change in velocity is an acceleration
Acceleration can be positive or negative
(deceleration)
Describe the acceleration in each of the sections
1 - 6
6
Calculating acceleration from a velocity-time
graph
Acceleration (Change in velocity) / Time taken
First Section a (20 - 0) / 2 20/2 10
m/s each second 10 m/s2
Now calculate the acceleration in the other
sections
7
Calculating distance moved from a velocity-time
graph
The AREA under a velocity-time graph is equal to
the distance moved. Divide the area under the
graph into rectangles and triangles Calculate
the area under each section to obtain the
distance moved for that section. Area of
triangle 1/2 x base x height Area of rectangle
length x width
8
Calculating distance moved from a velocity-time
graph
Distance moved for Section 1 1/2 x base x
height 1/2 x 2 x20 20 m Distance moved for
Section 2 width x height 2 x 20 40 m