Question

please tell me answer of this question
and d option is 2πr​

Answer 1

Given:

• A particle is moving in a circular path of radius r

To find:

• Displacement after half a circle

Solution:

Firstly , here A , B are the points at the centre of edge & the particle travells half of the circle that means point A to point B , the centre of circle is point O. Joining the three points line AOB will for that line is the diameter of the circle . Here line AO & line OB are the radii & both the radii AO & OB are connected will form line AOB = Diameter . Since , the particle travell from A to B in a semicircle the displacement will be the diameter.

In other form

♦ line AOB = AO + OB

♦ Diameter = displacement

♦ line AOB = Diameter → AO + OB = r + r = 2r

Hence , displacement of the particle = 2r [ option C ]

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Note 1 : The answer is not option d because , circumference of circle that means distance travelled total circle = 2πr . Here, the question is about the displacement at half of the circle not the distance at total circle.

Note 2 : Refer the attachment