# Maths moments question

The question:
Find the total moment of two equal and opposite forces of 25 N acting on a corkscrew, along lines 10 cm apart?

I got 0 but it says its incorrect,
With the given information if the magnitude of the forces are equal and the distance is symmetrical how can the answer not be 0. I'm new to moments so might be a basic mistake
Original post by ffffffffffffff.
The question:
Find the total moment of two equal and opposite forces of 25 N acting on a corkscrew, along lines 10 cm apart?

I got 0 but it says its incorrect,
With the given information if the magnitude of the forces are equal and the distance is symmetrical how can the answer not be 0. I'm new to moments so might be a basic mistake

You add moments clockwise/anticlockwise not linearly. What you probably have is a couple
https://physicsnet.co.uk/a-level-physics-as-a2/mechanics/moments/
so (probably) add the two moments
Original post by mqb2766
You add moments clockwise/anticlockwise not linearly. What you probably have is a couple
https://physicsnet.co.uk/a-level-physics-as-a2/mechanics/moments/
so (probably) add the two moments

so in this case it would be 2.5+2.5= 5NM which I tried and it said its also incorrect
Original post by ffffffffffffff.
so in this case it would be 2.5+2.5= 5NM which I tried and it said its also incorrect

Draw the (couple) diagram at the bottom of the previous link, then make sure you have the right distance for each of the moments.
Original post by ffffffffffffff.
so in this case it would be 2.5+2.5= 5NM which I tried and it said its also incorrect

The correct answer was 2.5 unsure why as that's only accounting for the moment of one force and it asks for total moment
Original post by ffffffffffffff.
The correct answer was 2.5 unsure why as that's only accounting for the moment of one force and it asks for total moment

See previous post. You can take moments about anywhere so normally youd do it in the centre, but you seem to be taking it about a point where one of the forces acts. You can do that, but one of the moments would be zero, not 2.5.
(edited 2 months ago)