Question

The speed - time graph for a vehicle moving in a straight line is shown in Fig. During the 25s, the average speed of the vehicle is. (a) 10 m/s (b) 12 m/s (c) 15 m/s (d) 8 m/s speed ​

Answer 1

Answer:

• The average speed during 25 seconds is 10 metre per second.

Using concept:

• Average speed formula

Using formula:

• ${\small{\underline{\boxed{\pmb{\sf{v \: = \dfrac{s}{t}}}}}}}$

Where, s denotes total distance, t denotes time taken and v denotes average speed.

Explanation:

~ Firstly let us find out the distance travelled by calculating the area of first triangle.

→ s = Area under curve

→ Distance = Area under curve

→ Distance = Area of triangle

→ Distance = ½ × B × H

→ Distance = ½ × (10-0) × (20-0)

→ Distance = ½ × 10 × 20

→ Distance = ½ × 200

→ Distance = 1 × 100

→ Distance = 100 m

~ Now let us find out the area of second triangle by using suitable formula!

→ s = Area under curve

→ Distance = Area under curve

→ Distance = Area of triangle

→ Distance = ½ × B × H

→ Distance = ½ × (25-10) × (20-0)

→ Distance = ½ × 15 × 20

→ Distance = ½ × 300

→ Distance = 1 × 150

→ Distance′ = 150 m

~ Now let us find out the total distance by using suitable formula!

→ Total distance = Distance + Distance′

→ Total distance = 100 + 150

→ Total distance = 250 m

~ Now let's see what is the total time given by using graph!

→ Total time = 25 - 0

→ Total time = 25 sec

~ Now calculating average speed by using suitable formula!

→ Average speed = Total distance/Total time taken

→ v = s/t

→ v = 250/25

→ v = 10 mps

→ Average speed = 10 mps