Key Points

✓Gravity is a force of attraction between objects with mass.
✓The more massive an object, the stronger its gravity.
✓Gravity keeps planets in orbit around the Sun.
✓The strength of gravity decreases with distance.
✓Gravity is what keeps us on the ground.

Gravity is a force that pulls objects with mass towards each other. The more massive an object is, the stronger its gravitational pull. That's why the Earth, being so massive, pulls everything towards its center – keeping us on the ground! Gravity is what keeps the planets orbiting the Sun and the Moon orbiting the Earth. It affects everything, from dropping a ball to the tides in the ocean. The strength of gravity depends on the masses of the objects and the distance between them; the closer they are, the stronger the pull.

Worked Example

A ball with a mass of 0.5 kg is dropped from a height. What force does gravity exert on the ball?

Step 1: Identify the known values. Mass (m) = 0.5 kg, acceleration due to gravity (g) = 9.8 m/s²
Step 2: Use the formula: Force (F) = mass (m) x acceleration due to gravity (g)
Step 3: Substitute the values: F = 0.5 kg x 9.8 m/s²
Step 4: Calculate the force: F = 4.9 N

Answer: The force of gravity on the ball is 4.9 Newtons.

Try It Yourself

1. What happens to the gravitational force between two objects if the distance between them increases?

2. Object A has a mass of 10 kg and Object B has a mass of 20 kg. Which object experiences a greater gravitational force from the Earth?

3. Two planets have the same mass. Planet X has a radius twice as large as Planet Y. If an object weighs 100 N on Planet Y, what would it weigh on Planet X?

Watch Out For These Mistakes

Thinking gravity only affects things on Earth.
Believing heavier objects fall faster than lighter objects (in a vacuum).
Confusing mass and weight.