Q8 of 59 Page 254

Give Reasons for the Following:

Can a body move with constant acceleration but with zero velocity? If yes, why?

Acceleration is the rate of change of velocity. In order to have non-zero acceleration, rate of change of velocity should be non-zero.

Yes, it is possible to have non-zero acceleration at zero velocity. But it is only possible for a moment. A moment is a brief period that cannot be measured.


Let us understand it by following two examples:


a) When we throw a ball in the air, it attains a maximum height and then comes down. At the maximum height velocity of the ball is zero, but a negative acceleration due to gravitation acts on it.


b) When we apply brakes on a moving car, the car stops and the velocity of the car is zero at that moment but acceleration (retardation) is not zero.


More from this chapter

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6

Give Reasons for the Following:

In a long distance race, the athletes were expected to take four rounds of the track such that the line of finish was same as the line of start. The motion of the athlete is non-uniform. Why?

 7

Give Reasons for the Following:

If the reading on the odometer of a vehicle in the beginning of a trip and after 40 minutes were 1048 km and 1096 km respectively, will the reading on the speedometer show this velocity where the vehicle is moving? Support your answer with reason.

 9

Give Reasons for the Following:

Can a body move horizontally with acceleration in vertical direction? If yes, why?

 10

Give Reasons for the Following:

Can a body move with a constant velocity in an accelerated motion? If yes, give reason.