Chapter 07 Motion Questions-02
Questions
1. Distinguish between speed and velocity.
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Answer
| Speed | Velocity |
|---|---|
| Speed is the distance travelled by an object in a given interval of time. |
Velocity is the displacement of an object in a given interval of time. |
| Speed = distance / time | Velocity = displacement / time |
| Speed is scalar quantity i.e. it has only magnitude. |
Velocity is vector quantity i.e. it has both magnitude as well as direction. |
2. Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
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Answer
The magnitude of average velocity of an object is equal to its average speed, only when an object is moving in a straight line.
3. What does the odometer of an automobile measure?
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Answer
The odometer of an automobile measures the distance covered by an automobile.
4. What does the path of an object look like when it is in uniform motion?
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Answer
An object having uniform motion has a straight line path.
5. During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of light, that is, $3 \times 10^{8}$ $m s^{-1}$
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Answer
Speed $=3 \times 10^{8} m s^{-1}$
Time $=5 \min =5 \times 60=300$ secs. Distance $=$ Speed $\times$ Time
Distance $=3 \times 10^{8} m s^{-1} \times 300$ secs. $=9 \times 10^{10} m$
