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cc100
24-07-2003, 05:17 PM
a stress of 3.2MN m -2 is applied to a sample of material.
this requires a force of 80N.

use the following formula to calculate the area over which that force acts.

note MN m-2 is equal to N mm-2 so u dont need to do any unit conversions.

you will need to rearrange the formula

STRESS= FORCE/AREA.

Sticks
24-07-2003, 08:55 PM
Area = Force / Stress

Area = 80N / 3.2 Nmm-2

Newton units cancel
1 over 1/a = a

so units of answer are in mm^2

Numerical answer is therefore

25mm^2

or in conventional units as we were taught.

2.5 x 10^-5 m^2

cc100
25-07-2003, 03:25 PM
very good, very quick.

have you solved that one you left me before??

Sticks
25-07-2003, 05:46 PM
I was waiting for your solution to that one :devil::laugh: