1D Motion Class 9 Physics | Distance, Displacement, Speed & Velocity and Acceleration Explained”

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🚀 1D Motion – Assertion & Reason

1. Assertion: Distance is always positive.
Reason: Distance is a scalar quantity.

Both true, R explains A Both true, R not explanation A true, R false A false, R true

2. Assertion: Displacement can be zero.
Reason: A body can return to its starting point.

Both true, R explains A Both true, R not explanation A true, R false A false, R true

3. Assertion: Speed is always equal to velocity.
Reason: Speed has no direction.

Both true, R explains A Both true, R not explanation A true, R false A false, R true

4. Assertion: Velocity can be negative.
Reason: Velocity has direction.

Both true, R explains A Both true, R not explanation A true, R false A false, R true

5. Assertion: Acceleration can be zero.
Reason: Velocity may remain constant.

Both true, R explains A Both true, R not explanation A true, R false A false, R true

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🧠 HOTS

1. Can distance be zero? When?

Yes, when object does not move.

2. Give example where displacement is zero but distance is not.

Walking in a circle and returning to start.

3. Why is velocity important?

It gives both speed and direction.

4. What is uniform motion?

Motion with constant velocity.

5. Can acceleration be negative?

Yes, it is called retardation.