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# Which of the Following Are Not Correct?The Basic Unit of Time is Second.,Every Object Moves with a Constant Speed.Distances Between Two Cities Are Measured in Kilometres. - CBSE Class 7 - Science

ConceptConcept of Speed

#### Question

Which of the following are not correct?

(1) The basic unit of time is second.

(2) Every object moves with a constant speed.

(3) Distances between two cities are measured in kilometres.

(4) The time period of a given pendulum is not constant.

(5) The speed of a train is expressed in m/h.

#### Solution

1) Correct

Second is the SI unit of time.

2) Not correct

An object can move with constant or variable speed.

3) Correct

The distance between two cities can be very large. Since kilometre is a bigger unit of distance, the distance between two cities is measured in kilometres.

4) Not correct

Time period of a pendulum depends on the length of the thread. Hence, it is constant for a particular pendulum.

5) Not correct

The speed of a train is measured either in km/h or in m/s.

Is there an error in this question or solution?

#### APPEARS IN

NCERT Solution for Science Textbook for Class 7 (2018 to Current)
Chapter 13: Motion and Time
Q: 2 | Page no. 156
Solution Which of the Following Are Not Correct?The Basic Unit of Time is Second.,Every Object Moves with a Constant Speed.Distances Between Two Cities Are Measured in Kilometres. Concept: Concept of Speed.
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