Gravity Basics
What is gravity, and how does it affect objects near Earth's surface?
Gravity is a force that pulls objects toward the center of the Earth. It makes things fall and keeps us on the ground.
Explain why an object in circular motion (like a satellite or the moon) doesn’t fly off into space.
Gravity pulls the object inward (Downward), preventing it from flying away and keeping it in orbit.
What is a projectile? Give an example from everyday life.
A projectile is an object that moves through the air under the influence of gravity, like a thrown ball or a kicked soccer ball.
How does the mass of two objects affect the gravitational force between them?
The greater the mass of the objects, the stronger the gravitational force between them.
What is a normal force?
The normal force is the upward force a surface applies to support the weight of an object resting on it.
Explain what it means when we say that Earth is accelerating.
Earth is constantly changing its direction as it orbits the Sun. This change in direction means it is accelerating, even though its speed stays constant.
How is gravity involved in keeping planets in orbit?
Gravity from the Sun pulls the planets inward while their speed keeps them moving forward, creating a balanced orbit.
Describe how gravity influences the motion of a projectile.
Gravity pulls the projectile downward, giving it a curved path instead of a straight line.
What happens to the gravitational force if the distance between two objects increases?
The gravitational force decreases as the distance increases.
If you are standing on the ground, what two forces are acting on you, and how do they balance?
Gravity pulls you down, and the normal force from the ground pushes you up, balancing each other out.
What would happen if gravity were suddenly "turned off" for an object in motion?
The object would move in a straight line at the same speed it was going before gravity was "turned off."
If an object in circular motion suddenly lost its velocity, what would happen?
It would stop moving in a circle and fall straight toward the center of the object it was orbiting.
Why doesn’t a projectile keep going straight forever after being thrown?
Gravity pulls it downward, changing its path into a curve.
How would the gravitational force between two objects change if one object’s mass became much larger?
The gravitational force would increase because the force depends on mass.
What would happen to the normal force if gravity increased?
The normal force would also increase to balance the stronger pull of gravity.
Why does gravity pull objects down instead of pushing them up?
Gravity is a force that pulls objects with mass toward each other.
Why don’t we feel the gravitational pull from the moon the same way we feel Earth’s gravity?
The moon is much farther away, so its gravitational pull on us is much weaker than Earth's.
How does the angle at which a projectile is launched affect how far it travels?
The angle affects the height and distance. A 45-degree angle usually makes the projectile travel the farthest.
Why do we feel Earth's gravitational pull but not the pull of smaller objects like a book or a chair?
Earth has much more mass than a book or a chair, so its gravitational pull is much stronger.
What happens to the normal force if you carry a heavy backpack while standing on the ground?
The normal force increases because it has to support both your weight and the weight of the backpack.
Why does gravity act on all objects equally, regardless of their mass, when they are in free fall?
All objects fall at the same acceleration (9.8 m/s² on Earth) because gravity pulls harder on heavier objects, but they also have more inertia, which balances out.
Why does an object in circular motion need to maintain a balance between its speed and the gravitational force acting on it?
If the speed is too low, gravity will pull the object inward. If the speed is too high, the object will fly off into space.
What happens to a projectile’s vertical and horizontal motion if air resistance is removed?
The horizontal motion stays constant, and the vertical motion is only affected by gravity, creating a curved path.
Why does the gravitational force between two objects never completely disappear, even if they are very far apart?
Gravitational force gets weaker as the distance increases, but it never completely disappears because gravity acts over infinite distances,
What happens to the normal force if you stand in an elevator that is moving upward?
The normal force increases because the floor has to push harder to support you while the elevator accelerates upward.