8th Grade Motion Assessment PS2-4

First & Last Name

Answer explanation

The question asks for both the first and last name, which are essential components of a full name. Providing both ensures clarity and completeness in identifying an individual.

1. What does the strength of the force of gravity depend on?

• The masses of the objects and their speed

• The mass and weight of the objects

• The masses of the objects and the distance between them

• The length of the object and its speed

Answer explanation

The strength of the force of gravity depends on the masses of the objects and the distance between them, as described by Newton's law of universal gravitation. The correct choice highlights these key factors.

Tags

NGSS.MS-PS2-4

2. What is the definition of inertia?

• The force of a push or a pull on an object

• The force pulling us towards the Earth

• increasing force because of increased mass of an object

• The tendency of an object to resist change in motion

Answer explanation

Inertia is defined as the tendency of an object to resist change in motion. This means that an object will remain at rest or in uniform motion unless acted upon by an external force, making this the correct choice.

Tags

NGSS.MS-PS2-2

3. What controls the orbits of objects in our solar system?

• Speed and light

• Inertia and gravity

• Gravity and speed

• Momentum and inertia

Answer explanation

The orbits of objects in our solar system are controlled by inertia, which keeps them moving, and gravity, which pulls them towards larger bodies like the Sun. Together, they create stable orbits, making 'Inertia and gravity' the correct choice.

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4

4. Our solar system is part of the

• Milky Way Galaxy

• Andromeda Galaxy

• Magellan Galaxy

• Perseus Galaxy

Answer explanation

Our solar system is located within the Milky Way Galaxy, which is a spiral galaxy containing billions of stars, including our Sun. The other options, like Andromeda and Magellan, are different galaxies.

Tags

NGSS.MS-ESS1-2

5. What is the shape of the Milky Way Galaxy?

• elliptical

• oblong

• spiral

• irregular

Answer explanation

The Milky Way Galaxy is shaped like a spiral, characterized by its distinct arms that extend outward from the center. This structure is typical of spiral galaxies, making 'spiral' the correct answer.

6. How many stars are estimated to be in the Milky Way Galaxy?

• Less than 100,000

• At least 100 billion

• About 1000

• About 100 million

Answer explanation

The Milky Way Galaxy is estimated to contain at least 100 billion stars, making 'At least 100 billion' the correct choice. Other options significantly underestimate the number of stars in our galaxy.

7. The gravitational force of the sun is the sole reason the planets and other bodies orbit around it, holding the solar system together.

• True

• False

Answer explanation

False. While the sun's gravitational force is a major factor in holding the solar system together, other forces, such as the gravitational interactions between planets and the effects of their own motion, also play significant roles.

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4

In diagram A, describe the relationship between distance and force of gravity.

Answer explanation

In diagram A, as the distance between two masses increases, the force of gravity decreases. This inverse relationship shows that gravity weakens with greater separation, following the formula F = G(m1*m2)/r^2.

How does the length of each arrow show its relative strength?

Answer explanation

The length of each arrow represents its relative strength; longer arrows indicate greater strength, while shorter arrows signify less strength. This visual representation allows for easy comparison of different strengths.