Question

d) Pranavi walks along a straight road from point A to point C. Pranavi takes 70 minutes
to cover the distance AC. She then turns back and takes 50 minutes to cover the
distance CA. She then walks five times on the same road in a similar manner and it
takes 120 minutes to complete each round.
The type of motion shown by Pranavi will be
(i) only rectilinear motion.
(ii) only periodic motion.
(iii) both rectilinear and periodic. (iv) neither rectilinear nor periodic.​

Answer 1

The motion is :

• BOTH RECTILINEAR AND PERIODIC.

But why ??

• First of all, the motion is one dimensional, that means that the person is travelling along a single straight line. Hence, the motion can be stated as RECTILINEAR.

• Also, the person is able to complete whole trajectory in (50 + 70) = 120 min everytime.

• So, a fixed amount of time is required to complete the whole oscillation, hence it's PERIODIC.

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• One more thing to note is that: this motion may be oscillatory and periodic, however we cannot term this as SIMPLE HARMONIC MOTION.

• This is because the force experienced doesn't vary with displacement as F=(-kx).

$\star$ Hope It Helps.