Question 1 What is the nature of graph for a uniform speed?

Question 2 Name the quantity which is measured by the area occupied under the velocity-time graph?

Question 3 What does the slope of speed-time graph indicate?

Question 4 What can you say about the motion of a body if its displacement-time graph is a straight line?

Question 5 What can you say about the motion of a body if its velocity-time graph is a straight line?

Question 6 Name the quantity, the slope of whose graph give Speed?

**Graphical Representation of Motion**

**Distance – Time graphs**

**(1) Uniform Speed**

Straight line graph between distance and time tells us that body is moving with uniform speed. Slope of distance time graph indicates speed.

Slope = PQ/OQ

**(2)** **Non-Uniform speed**

The distance time graph for a non-uniform motion is a curved line (parabola). If a body moves with a non-uniform speed then its motion is said to be accelerated. It also represents distance time graph with accelerated motion.

**Speed – Time or velocity – Time Graphs**

**(1)** **Speed-time graph when speed remains constant**

(a) Speed time graph for a body moving with constant speed(no acceleration) is a straight line parallel to time axis. We can find the distance travelled by a body in a given time from speed-time graph.

Speed = Distance travelled / Time taken

OC x BC = Distance travelled

OC x OA = Time taken

Distance travelled = Area of rectangle OABC

The velocity time graph of an object moving with constant velocity is a straight line parallel to time axis.

**(2)** **Speed-time graph when speed changes at uniform rate (uniform acceleration)**

(1) When a body moves with uniform acceleration ,its speed changes by equal amount in equal intervals of time.

Speed time graph for a uniformly changing speed will be a straight line.

The value of acceleration from speed time graph of moving body can be calculated as:

a = Change in speed or velocity / Time taken

a = PQ/OQ

In a speed time graph the acceleration is given by slope of the graph.

The distance travelled by a moving body in a given time can be calculated from speed time graph.

Distance travelled = Area of triangle POQ

= 1/2 x OQ x OP

In a speed time graph of a body a straight line sloping downwards indicates retardation.

**Speed time graph when the initial speed of the body is not zero**.

The distance travelled by the body in this case is equal to the area of trapezium OBCA.

Area of Trapezium = (Sum of parallel sides x Height) / 2

Distance Travelled = ((OB + AC) x OA)/2

**(3) Speed – Time graph when speed changes at a non-uniform rate (Non-uniform acceleration)**

When the speed of a body changes in an irregular manner, then speed-time graph of a body is curved line.

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Richa kumari says

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Bhavesh kumar says

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Niya says

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