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#1 2011-11-18 03:11:30
Motion
The speed of a train increases at a constant rate a from zero to v and then remains constant for an interval and finally decreases to zero at a constant rate b. L is the total distance traveled. Then Time=? 
Last edited by Agnishom (2011-11-18 03:12:33)
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#2 2011-11-18 07:41:04
- Bob
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- Registered: 2010-06-20
- Posts: 10,649
Re: Motion
hi Agnishom,
The graph below is a velocity / time graph. The area under the graph (shaded) is the total distance travelled.
(Note. The squares are illustrative only.)
Acceleration = change of velocity / time => time = v / a for the first part and v / b for the deceleration.
Let the total time be T. So the time at constant velocity is T - v/a - v/b
Calculate the area and set it equal to L.
Make T the subject of the equation.
Bob
ps.. Still working on the integration. That bit of memory is very rusty. 
Last edited by Bob (2011-11-18 07:43:37)
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