Object A attracts object B with a gravitational force of 5 newtons from a given distance. If the distance between the two objects is reduced in half, what will be the changed force of attraction between them?
Answer:
20 N
Explanation:
The gravitational force between the two objects is given by:
\(F=G\frac{m_A m_B}{r^2}\)
where
G is the gravitational constant
mA and mB are the masses of the two objects
r is the separation between the two objects
In this situation, we have that the distance between the two objects is reduced in half. Let's call the new distance
\(r'=\frac{r}{2}\)
So the new gravitational force F' will be
\(F'=G\frac{m_A m_B}{r'^2}=G \frac{m_A m_B}{(\frac{r}{2})^2}=4 G \frac{m_A m_B}{r^2}=4 F\)
So, the force increases by a factor 4, therefore the new force will be
\(F'=4F=4 \cdot 5 N=20 N\)