- #1

- 19

- 0

- Homework Statement:
- as below

- Relevant Equations:
- as below

So I let x be the distance from P.

I then considered moments about R and got this:

1) (40g)(x-3) = 40gx - 120g and this is anticlockwise

2) (30g)(0.5) = 15g and this is anticlockwise

3) (2.5g)(2) = 5g and this is clockwise

And then by equating clockwise and anticlockwise I get this:

40gx - 120g + 15g = 5g

40gx = 110g

x = 110/44

x = 2.75m

But the mark scheme says this is wrong? They've got it as 3.25m. This is what they used as moments about R:

(40g)(x-3) + (2.5g)(2) = (30g)(0.5)

I don't get how they can consider the boy and the box Q to be on the same side??