Question

Ted wants to hang a wall clock on the wall by using a string. If the mass of the wall clock is 0.250 kilograms, what should be the tension of the string so that it can sustain the weight of the wall clock?

Answer 1

The answer is 2.45 newtons because 1 kg = 9.8 newtons so when we use that ratio, we get around 2.45 newtons for 0.25 kg. This would be your (B) option I think.

Answer 2

The clock is pulling the force towards earth's center because of gravity.
That force is equal to:
F = m*g where g is gravitational acceleration.

We will take that g = 9.81m/s^2

Now:
F = 0.25 * 9.81 = 2.4525 N

The string needs to sustain that force, therefore minimum Force that string has to be able to sustain is:
2.4525 N