Q15 of 35 Page 55

What is the numerical ratio of velocity to speed of an object?

We all know that:

..1


And also, ..2


Now, we also know that distance travelled by a body is the actual path length covered by the moving body, whereas displacement is the shortest distance between the initial position and the final position along with direction.


So, ..3


Now, from equation 1 and 2, we can deduce that:


..4


Now, from 3 and 4 we get that:



Note: or velocity = speed is valid for a straight line motion.


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A particle travels half the distance of a straight journey with speed 5 ms–1. The remaining part of the distance is covered with speed 6 ms–1 for half of the remaining time and with speed 4 ms–1 for the other half of the remaining time. The average speed of the particle is?

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A person travels along a straight road for the first t/3 time with a speed v1 and for next 2t/3 time with the speed v2 then the mean speed v is given by?

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A person standing on an escalator takes time t1 to reach the top of a tower when the escalator is moving. He takes time t2 to reach the top of the tower when the escalator is standing. How long will he take if he walks up to a moving escalator?

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A stone thrown upward from the top of a tower 85m high reaches the ground in 5 s

(a) Calculate the greatest height above the ground


(b) The velocity with which it reaches the ground


(c) The time taken to reach the maximum height (g = 10ms–2)