Question

Q19. The velocity-time graph of an object is shown below.(a) Identify the kind of motion of the object represented by the lines OA and BC.(b) With what velocity the object is moving at t=8 seconds?(c) Calculate the acceleration of the object in the following cases:(i) Between the third and tenth second.(ii) During the last two seconds​

Answer 1

Answer:

i) The motion represented by OA is accelerated motion while the motion represented by BC is decelerated motion.  

ii) Acceleration of the lift during first 2 seconds = 4.6 / 2 = 2.3 m/s2  

iii) Acceleration between third and tenth second = 0  

iv) Acceleration during last 2 seconds = 0 - 4.6/2 = - 2.3 m/s2

Explanation:

Answer 2

Concept:

Velocity is the directional speed of an object in motion. Velocity is defined as the rate of change of distance of the object with respect to time.

Given:

The velocity-time graph.

Find:

The kind of motion of the object represented by the lines OA and BC.

With what velocity the object is moving at $T=8$ seconds.

The acceleration of the object in the following cases:

(i) Between the third and tenth second.

(ii) During the last two seconds​

Solution:

The motion shown by $OA$ is accelerated on the other side, the motion symbolized by $BC$ is decelerated.

Now, at $T=8sec$

The acceleration of the lift in the first two seconds is $4.6m/s$.

Therefore, the velocity of the object at $T=8sec$ is :

$V=4.6m/s$

The acceleration of the object at $T=8sec$ is $V=\frac{4.6m/s}{2s}=2.3m/s^2$.

From the velocity-time graph, there is no acceleration of the object between the third and tenth seconds.

From the velocity-time graph,

The acceleration of the object during the last two seconds is:

$=0-\frac{4.6}{2}\\ =-2.3m/s^2$

Speed-time graphs are sometimes known as velocity-time graphs. The velocity of the item is the vertical axis of a velocity-time graph. The horizontal axis is represented by time.

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