Question

The graph shows the speed of a car as it moves from rest. Find average speed in 3s

Answer 1

Answer:

Correct option is

A

X

Explanation:

We know that the slope of the speed-time graph gives acceleration.

Acceleration =

dt

dv

In region X :

the graph has positive slope .i.e.

dt

dv

>0

In region Y :

the graph has Zero slope. i.e.

dt

dv

=0

So, the car is accelerating in region X

Answer 2

Answer: The average speed is 12 ms^-1

Explanation: First finding the distance using second equation of motion ( S = ut + 1/2 at^2 .

S = (0)(3)+1/2 (4)(3)^2

S = 18 m

Now finding speed : Distance/Time

18 m / 3 s

Average speed = 6 m/s^-1