## Homework Statement

A horizontal, 10-m plank weighs 100 N. It rests on two supports that are placed 1.0 m from each end as shown in the figure. How close to one end can an 800-N person stand without causing the plank to tip?

## The Attempt at a Solution

I know the person weighs 800 and there is X distance

so I have 800N from the weight of the person plus 10 N from the weight of the plank on the right side of the fulcrum

800X + 10 N = 90 N (the weight of the rest of the plank)

#### Attachments

• Question 26 (ch 7-9 test).png
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jedishrfu
Mentor
Isn't the formula F x Dist so that for this case (800 + 10) * X and the length on the other side would be?

Isn't the formula F x Dist so that for this case (800 + 10) * X and the length on the other side would be?

the length of the other side would be 90 meters which equates to 90N

BvU
Homework Helper
Not good.
On the left we have 90 N * 4.5 m (as we had in October...)
On the right we have
from the person: 800 * (1-X) if X is the distance from the end of the plank
from the plank: 10 N * 0.5 m (Haru's "the rest of the plank")

Now balance the lot and you're done.

Good luck with the exam :)