# How do I figure out the normal force on a person on an accelerating platform? [closed]

My question is an elaboration on this question: Force on rope with accelerating mass on pulley

The elaboration is to determine what the Force that the platform exerts on the person. Assume the platform has mass M1 and the person has mass M2.

If I draw a Free body diagram, I get

1. $F_n$ - Normal force what I'm looking for... (upward)
2. $F_t$ - Reactive force from person pulling down on rope (upward)
3. $mg$ - Person's weight (downward)

All these forces sum up to equal the $g/5$ acceleration. Mathematically,

• $F_n + F_t - mg = ma$

• $F_n = ma + mg - F_t$

• $F_n = M_2a + M_2g - \frac{3(M_1+M_2)g}{5}$

Is this right..?

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Hi Mister C, and welcome to Physics Stack Exchange! We don't really entertain these work-checking questions unless you also include some reason to believe your work is wrong. Do you have such a reason? If so, edit it into the question and you can flag it for moderator attention to get it reopened. – David Zaslavsky Oct 19 '12 at 14:03

## closed as too localized by David Zaslavsky♦Oct 19 '12 at 14:02

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