What two factors affect the force of Gravity

What two factors affect the force of Gravity? Gravity It’s Universal – it’s everywhere!

Gravity is a weak force, this means that the force of gravity is noticeable unless there is a very large mass involved (such as a planet or star). That’s why we are not revolving around one another! But the Earth and Moon are large enough! Gravity is universal

Gravity depends on mass Less mass means less gravitational force More mass means more gravitational force

Newton’s Law of Universal Gravitation Gravity pulls objects in a straight line towards each other. Earth and Moon

Gravity depends on the distance between More distanceobjects means less gravitational force Less distance more gravitational means force Think of gravity like a magnet. When magnets are closer, the attraction is stronger. When magnets are further apart, the attraction is less.

What two factors affect the force of Gravity? Gravity It’s Universal – it’s everywhere! MAS S DISTANC E

Gravitational Acceleration �So all objects “want” to fall at 9. 8 m/s/s on the surface of the earth. Gravity mini-experiment: 1. Crumble up (compress) a piece of paper. 2. Drop the paper from the height of your desk to the floor. 3. Leave a piece of paper flat. Answer in your notebook 4. Drop the paper from the height of your desk to the floor. 5. Observe how each object falls. Discussion: �Both object “want” to fall at 9. 8 m/s/s. Did each object

APOLLO 15 THE HAMMER AND THE FEATHER http: //www. teachertube. com/video/ham mer-and-feather-drop-on-moon-41342 Before you watch the video. All objects fall at the same rate in a gravitational field. Normally air resistance would slow down the feather. On the moon there is no air so it is easy to see that gravitational fields accelerate all objects at the same rate.

ADJUSTING TO LIFE BACK ON EARTH �Astronauts in Space Washing hair in space: http: //www. space. com /21946 -how-to-washhair-space-video. html �Sometimes astronauts have a little trouble adjusting to life back on Earth Adjusting back to life on Earth: http: //www. space. com/ 23672 -adjusting-to-lifeback-on-earth-karennyberg-talks-to-spacecom-video. html

Gravitational Acceleration �All objects on the surface of the earth accelerate downward at 2 regardless Remember As the forceof and mass change acceleration stays 9. 8 m/s. F=ma mass. Why? the(Think about the same. inertia…)100 kg 10 kg Write this in your notes! Gravitational acceleration g = 9. 8 m/s 2 More mass means more gravity, but it also means more inertia. The extra gravity gets cancelled out by the extra inertia, so all objects fall at the same speed regardless of mass.

Read this slide! Weight Gravity’s Effect on Mass Weight = Mass x Acceleration of Gravity W(Newtons) = m (kg) g(Meters/Sec ) 2 9. 8 (Newtons) =1 (kg) 9. 8(Meters/Sec ) 2

Write this in your notebook! Word Magnet: What is Gravity? Attractive force Gravitational Force depends on the total mass of the two objects Property of Matter Gravit y Considered to be a weak force Gravitational Force depends on the distance between the two objects One of the four forces of nature

INVESTIGATING GRAVIT Y

INVESTIGATING GRAVIT Y Answer in your notebook

INVESTIGATING GRAVIT Y Think about Newton’s First Law? Read through these before you look at the next slide. You do NOT have to answer these in your notebooks. Does the cup have mass? Does the water have mass? Are the cup and water moving at the same rate? How fast does little g “want” to accelerate all objects?

Chapter 3. 1 – Gravity � When you complete the notes start working on your homework.