Graph included
according to the diagram, what is the half-life of the cobalt-57 isotope?
question 2 options:
50 days
120 days
24 days
10 days

10 days

Explanation:

The half-life of a radioactive sample is the time taken for half of the sample to decay.

In the diagram, the half-life corresponds to the time after which the % of cobalt-57 has halved. We can observe the following:

At t=10 days, the % of Co remaining is approximately 45%

At t=20 days, the % of Co remaining is approximately 22%

This means that the sample of cobalt-57 has halved in 10 days, so the half-life of cobalt-57 is 10 days.

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.