## The speed-time graph for a car is shown is Fig. 8.12.

##
(a) Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance travelled by the car during the period.

(b) Which part of the graph represents uniform motion of the car?

#### Answer

**
(b)
**

The part of the graph between time 6s to 10s represents uniform motion of the car

**
(a)
**

**
**

**
**

In a velocity − time graph,

Distance = Area of v-t Graph

Here, we find approximate area using Area of Triangle

Distance = Area Δ OAB

= 1/2 × b × h

= 1/2 × 4 × 6

= 12 m

But, this is an inaccurate method to find Area, since the red portion is

not covered

∴ Total area = 15.2 + 0.8 + 0.4 + 0

= 16.4 sq units

Area under v − t graph gives distance

Hence, the distance covered by the car in 0−4 s =
**
16.4 m
**