If the mass of an object doubles, what happens to the gravitational force between that object and other object that keeps a constant mass. Assume that the distance between the two objects remains the same. (1 point)

Let's address each of your questions one by one:

1. **Gravitational Force with Increased Mass**:
The gravitational force \( F \) between two objects is given by Newton's law of gravitation:
\[
F = G \frac{m_1 m_2}{r^2}
\]
where \( G \) is the gravitational constant, \( m_1 \) and \( m_2 \) are the masses of the objects, and \( r \) is the distance between their centers. If the mass of one object doubles (let's say \( m_1 \) doubles to \( 2m_1 \)), then the new force is:
\[
F' = G \frac{(2m_1) m_2}{r^2} = 2 \cdot G \frac{m_1 m_2}{r^2} = 2F
\]
Therefore, the correct answer is: **The amount of the gravitational force doubles.**

2. **Samples Collected on Mars**:
If a person takes 9 samples in 4 days, the rate of samples per day is:
\[
\text{Rate} = \frac{9 \text{ samples}}{4 \text{ days}} = 2.25 \text{ samples/day}
\]
Over 10 days, the expected total number of samples is:
\[
\text{Total samples} = 2.25 \text{ samples/day} \times 10 \text{ days} = 22.5 \text{ samples}
\]
Hence, the correct answer is: **22.5**.

3. **New Orbital Period of Earth If Mass Doubles**:
The orbital period of an object in space is determined by the gravitational forces and is governed by Kepler's laws. Specifically, if the mass of Earth were to double, it would not affect the orbital period in the way specified, assuming distance from the Sun remains constant. The period does not depend on the mass of the orbiting body, but rather on the total mass of the system and the distance. Therefore, the new orbital period would still be approximately: **365 days**.

To summarize:
- Gravitational force doubles: **The amount of gravitational force doubles.**
- Samples in 10 days: **22.5**.
- New orbital period if Earth's mass doubles: **365 days**.