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प्रश्न
Which of the following can sometimes be 'zero' for a moving body?
(i) average velocity
(ii) distance travelled
(iii) average speed
(iv) displacement
पर्याय
only (i)
(i) and (ii)
(i) and (iv)
only (iv)
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उत्तर
(i) and (iv)
Distance is the length of the actual path covered by a moving body. This implies that the distance travelled by a moving body and also its average speed can never be zero at any point of time. However, it is possible for the displacement as well as average velocity for the body to be zero at an instance during the motion of the particle.
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संबंधित प्रश्न
In addition to speed, what else should we know to predict the position of a moving body ?
State whether speed is a scalar or a vector quantity. Give reason for your choice.
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A motorcyclist starts from rest and reaches a speed of 6 m/s after travelling with uniform acceleration for 3 s. What is his acceleration ?
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The graph given alongside shows how the speed of a car changes with time:
(i) What is the initial speed of the car ?
(ii) What is the maximum speed attained by the car ?
(iii) Which part of the graph shows zero acceleration ?
(iv) Which part of the graph shows varying retardation ?
(v) Find the distance travelled in first 8 hours.
When is a body said to be in motion?
Give one example of following motion :
Uniform velocity
A train is moving with a velocity of 90 km h-1 . It is brought to stop by applying the brakes which produce a retardation of 0.5 ms-2 Find :
(i) The velocity after 10 s , and
(ii) the time taken by the train to come to rest .
