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Question 1. Asked on :15 January 2019:06:06:35 PM

#### Explain why the below statements about displacements are not true.Displacements cannot be zeroDisplacements cannot be zeroThe magnitude of displacements are always greater than the distance travelled.The magnitude of displacements are always greater than the distance travelled.

-Added by Harshita Rathore Science » Motion

Himanshi Verma

(a) Not true, because if the initial and final position of the object is the same displacement can become zero.

(b) Not true, because, displacement is the shortest measurable distance between the initial and final positions of an object. It cannot be greater than the magnitude of the distance travelled by an object, but it can be smaller than the magnitude of the distance travelled by an object or , it may be equal to the distance travelled by the object.

-Answered by Himanshi Verma On 20 January 2019:05:21:27 PM

Question 2. Asked on :15 January 2019:06:04:35 PM

#### A man walks around a square street of side 10 m in 40 sec. Calculate the displacement of the man at the end of 2 minutes 20 seconds.

-Added by Himanshi Verma Science » Motion

Himanshi Verma

The man takes 40 sec to cover ( 4 * 10 ) 40 metres. This shows he covers one metre in one sec.

In 2 min 20 sec (140 sec) , he will cover a distance of  140 metres.

Thus he completes  14040 = 3.5 rounds in 2 min 20 sec.

Hence it is noticed that he will be at the opposite side from where he started.

Now considering two simple cases.

Case (i)

If the man started at a corner of the square street:

In this case, the man would be diagonally opposite to the place from where he started

Displacement = diagonal of square with side 10 metre.

=   102+102

=   100

=14.1m

Case (ii)

The man started from the middle of the road.

After the end time, he is in the opposite side of the road.

Hence, the displacement is 10 metre.

-Answered by Himanshi Verma On 19 January 2019:04:25:08 PM

Question 3. Asked on :07 January 2019:12:54:06 AM

#### What is retardation?

-Added by ATP Admin Science » Motion

Akki chauhan

Negative acceleration is called retardation.

-Answered by Akki chauhan On 10 January 2019:10:56:09 AM

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