The total distance is 4 + 7 = 11 Km
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 !
Answer:
It may seem as though burning destroys matter, but the same amount, or mass, of matter still exists after a campfire as before. Look at Figure 3.7.1 below. It shows that when wood burns, it combines with oxygen and changes not only to ashes, but also to carbon dioxide and water vapor. The gases float off into the air, leaving behind just the ashes. Suppose you had measured the mass of the wood before it burned and the mass of the ashes after it burned. Also suppose you had been able to measure the oxygen used by the fire and the gases produced by the fire. What would you find? The total mass of matter after the fire would be the same as the total mass of matter before the fire.
