Question

multiple choice 1 point
why does earth exert a stronger gravitational force on you than other nearby objects?
because earth has a magnetic field
because earth has more mass than any nearby object
because earth spins faster than other objects
because earth is closer to you

Explanation:

To determine why Earth exerts a stronger gravitational force on us than nearby objects, we use Newton's law of universal gravitation, \( F = G\frac{m_1m_2}{r^2} \), where \( F \) is gravitational force, \( G \) is the gravitational constant, \( m_1 \) and \( m_2 \) are masses, and \( r \) is the distance between them. Gravitational force depends on mass and distance. Nearby objects (like a book, table) have much less mass than Earth. Even though Earth is large (so \( m_1 \) is huge) and the distance \( r \) from us to Earth's center is significant, the massive difference in mass (Earth's mass is far greater than any nearby object's mass) makes its gravitational pull on us stronger. Let's analyze the options:

• "Because Earth has a magnetic field": Magnetic fields don't affect gravitational force. Eliminate this.
• "Because Earth spins faster than other objects": Earth's spin (rotational speed) doesn't influence gravitational force magnitude (gravity is about mass and distance, not spin rate for this context). Eliminate this.
• "Because Earth has more mass than any nearby object": This matches the gravitation law—greater mass means greater gravitational force (when distance is considered, but nearby objects are close, yet their tiny mass can't compete with Earth's huge mass).
• "Because Earth is closer to you": While distance matters, Earth's center is about 6,400 km from us, and nearby objects are much closer (e.g., a meter away). But according to \( F = G\frac{m_1m_2}{r^2} \), if mass were equal, closer would mean stronger force. However, nearby objects have negligible mass compared to Earth. So the key factor is mass, not just distance. So this option is incorrect.

Answer:

The correct option is: Because Earth has more mass than any nearby object