Name: Date: How Does Gravity Affect The Motion of Objects? Unit 3: Aim 13 On Earth, gravity pulls all objects to Earth’s center. The Law of Universal Gravitation states that all objects in the universe attract each other, therefore gravity acts on all objects in the universe. Although gravity affects all things, the attraction between two objects depends on a few things. One is MASS and the other is DISTANCE. As the mass of an object increases, the gravitational force increases. Since Earth is an object with a lot of mass, objects fall toward the center of the Earth with a noticeable amount of force. This is why it is easier to lift a ping-pong ball over your head than a bowling ball because there is less gravitational pull to overcome. With distance as a factor, as the distance between two objects increases, the gravitational force between then decreases Gravity acts on all masses equally, even though the effects on both masses may be different because gravity causes all objects to fall at the same constant rate of 9.8 m/s2. An object in free fall means that the only force acting on the object is gravity. If gravity acts on all masses equally, why do all objects have a different weight? The mass of something is the amount of matter something is made of. The mass of an object ALWAYS stays the same. Your mass on Earth will be the same if you were on the moon. Weight however, is a measure of the force of gravity acting on an object at the surface of a planet. The weight can CHANGE depending on how much the planet is pulling on the object. 1. Define the following: a. gravity: b. law of universal gravitation: c. mass: d. weight: e. free fall: 2. What are the two things that affect the attraction between two objects 3. Why is it easier to lift your puppy than to try to lift your car? 4. As you travel away from Earth’s surface. a. What happens to your mass? b. What happens to the gravitational pull? Does it increase or decrease and why?! c. What happens to your weight? 5. The sun pulls on a planet with 167,560,432 N of force. a. What will happen to that force, if the sun decreases in mass. b. What will happen to that force, if the planet moves closer to the sun. 6. Gravity is pulling down on a skydiver with 70 N of force, and air resistance is pushing up on the skydiver with 30 N of force. Draw a free-body diagram of this scenario. What is the net force on the skydiver? 7. What forces are acting on an object in free fall? If gravity is pulling on an object in free fall with 45,400 N of force, what is the net force on the object? So as you travel away from the Earths surface, your mass stays the same but your weight reduces as gravitational pull decreases Felix- jumped from a height of about 120,000 feet (mt Everest is only about 20,000 feet). The air is so thin at that altitude. Air pressure decreases as altitude increases, since less pressure is pushing the air molecules together, this change in density makes it easier for objects to move through .