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/sci/ - Science & Math

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1163039 No.1163039 [Reply] [Original]

A train 574 m long is moving on a straight
track with a speed of 87.7 km/h. The engineer
applies the brakes at a crossing, and later the
last car passes the crossing with a speed of
16.4 km/h.
Assuming constant acceleration, determine
how long the train blocked the crossing. Dis-
regard the width of the crossing.


Im getting 28.98seconds but im wrong...what are you guys getting?

>> No.1163050

bump

>> No.1163055

>The engineer applies the brakes at a crossing

>Assuming constant acceleration

wut

>> No.1163058

>>1163055
Acceleration can be negative lol

>> No.1163066

>>1163055
>Assuming constant acceleration
There is no such thing as de-acceleration. Only positive and negative acceleration.

>> No.1163081

>>1163039

A train 574 m long is moving on a straight
track with a speed of 87.7 km/h. The engineer
applies the brakes at a crossing, and later the
last car passes the crossing with a speed of
16.4 km/h.
Assuming a male engineer (naturally), determine
how long the engineer can go without asking a male passanger to suck his cock.

Im getting 28.98seconds but im wrong...what are you guys getting?


THOUGHT I WOULD FIX THAT 4 YA
>fix'ed

>> No.1163089

>>1163081
Cute, but train engineers aren't the same thing as real engineers, you retard.

>> No.1163090

<span class="math">V_f=V_o + a \dot t [/spoiler]
<span class="math">D=V_o \dot t + \frac{1}{2} \dot a \dot t^2 [/spoiler]
<span class="math">V^{2}_f = V^{2}_o + 2 \dot a \dot d [/spoiler]
Use these to find what you want.

>> No.1163214

>>1163090
Shouldn't that last one be:
V^2 = V^2 + a^2 * t^2 + 2 * at * V
What you wrote made no sense to me.

I gotta learn that jsMath thing. =P