Help ? write a CER paragraph to explain why fusion stops in the stars core once it reaches iron

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

1) estimating temperature to the nearest tenth of a degree

2) estimating the mass of the sample to the nearest tenth of a gram

4) the position of the cups of sand and water under the heat lamp