AQA GCSE Velocity time graphs and distance travelled(Physics)

Velocity time graphs and distance travelled

The area under a velocity time graph will show the distance travelled, or the displacement of an object. 

For these types of questions the area under the graph will normally have a shape e.g triangle or rectangle. 

 

Shape under the velocity time graph resembles a triangle

velocity time graph with a straight line

The area under the graph is shaded, in this case it is a triangle shape. 

The area of this triangle, will give the distance travelled, or displacement.

Area of a triangle = 1/2 x base x height

Distance travelled (Area of the triangle) = 1/2 x 2.5 x 25 = 31.3m

It is also possible to work out the area of each square, then count the number of squares.

Distance travelled = area of each square x number of squares

This alternative method is slightly harder to use, so the triangle method was used.

Shape under the velocity time graph resembles a rectangle

Velocity time graph with a horizontal line

The area under the graph is shaded, in this case it is  rectangle.

Velocity time graph with rectangle area shaded under the graph

Distance travelled (area of rectangle) = length x width

Distance travelled = 10 x 2.5 = 25m

It is also possible to work out the area of each square, then multiply by the number of squares, but this method can be slightly more tricky.

 

Shape under the velocity time graph resembles a combination shape

In some cases there will be two or more shapes present. We will look at this example below

Velocity time graph, combination shape under the line

Lets work out the total distance travelled

The area under the line has been split into two different shapes a triangle and a rectangle. 

Area of Rectangle = 15 x 2 = 30

Area of triangle = 1/2 x 15 x 2 = 15

Total area = 30 + 15 = 45

Total area under the graph = distance travelled

Total distance travelled = 45m.

Practice Question

1.What information can be found from the area under the graph.

2. Use the velocity time graph below to find the distance travelled in the first 8 seconds of the journey.

Velocity time graph question to find distance travelled using a horizontal line

3.Use the velocity time graph below to find the distance travelled in the first 8 seconds of the journey.

Velocity time graph with diagonal line to find distance travelled

4.Using your answers for questions 2 and 3, calculate the total distance travelled in both question 2 and 3.

 

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