Well I don't know !
Let's work it out.
The gravitational force between two objects is
F = G · M₁·M₂ / R² .
'G' is the 'universal gravitational constant'. We could look it up.
'M₁' is the mass of one object
'M₂' is the mass of the other object
'R' is the distance between their centers.
It looks complicated, but stay with me. We can do this !
We know all the numbers, so we can calculate the force.
'G' is 6.67 x 10⁻¹¹ newton·meter² / kg² (I looked it up. You're welcome.)
'M₁' is 15 kg
'M₂' is 15 kg
'R' is 0.25 meter.
Now it's time to pluggum in.
F = G · M₁·M₂ / R²
= (6.67 x 10⁻¹¹ newton·meter² / kg²) · (15 kg) · (15 kg) / (0.25 m²)
= (6.67 x 10⁻¹¹ · 15 · 15 / 0.0625) N·m²·kg·kg / kg²·m²
= 2.4 x 10⁻⁷ Newton .
That a force equivalent to about 0.00000086 of an ounce.
This is the answer to part-a.
Concerning the answer to part-b ...
Personally, I could not detect this force, no matter what kind of equipment
I had. But I am just a poor schlepper engineer, educated in the last Century,
living out my days on Brainly and getting my kicks from YouTube videos.
I am not pushing the box to the envelope, or thinking outside the cutting
edge ... whatever.
I am sure there are people ... I can't name them, because they keep a
low profile, they stay under the radar, they don't attract a lot of media
attention, their work is not as newsworthy as the Kardashians, and plus,
they seldom call me or write to me ... but I know in my bones that there
are people who have measured the speed of light to NINE significant figures,
aimed a spacecraft accurately enough to take close-up pix of Pluto ten years
later, and detected gravity waves from massive blobs that merged 13 billion
years ago, and I tell you that YES ! THESE guys could detect and measure
a force of 0.86 micro-ounce if they felt like it !
