Bell Work: Torque Review The force must be exerted ______ to the lever arm. The pivot point is called a _______. In equilibrium, the clockwise torque is equal to the ________ torque. The unit for torque is ______. Torque is calculated by multiplying _____ and ______.

You should have 15 bell work assignments for October * You should have 15 bell work assignments for October. * Please turn them in if you have them today. * Tomorrow is okay too. * Pick up a universal gravitation note guide.

Universal Gravitation Newton wrote this one too. It applies to everything in the universe!

What type of force allows a balloon to stick to the wall? Every mass in the universe reaches out and pulls on every other mass in the universe. Gravitational forces are the smallest forces in nature.

What forces are present in the nucleus of an atom? Most gravitational forces go unnoticed. Ex: Two pencils don’t roll towards each other on a desk. Ex: Cars in traffic aren’t attracted to each other. Gravitational force and weight are the same thing when you are on a planet.

What forces are present in the nucleus of an atom? Gravitational forces are affected by distance between the objects’ centers and both of their masses. Newton wrote the Universal Law of Gravitation:

Ever walk past a building and stick to it because of its gravitational pull? Symbol Measurement Unit FG Gravitational forces  N G Universal gravitational constant 6.67 x 10-11 Nm2/kg2 m1 First mass  kg m2  Second mass kg r (or d) Distance b/t objects centers  m

When have you felt less gravitational pull? more distance = less gravitational force; distance and force are inversely related less mass = less gravitational force; mass and force are directly related

Where can you go to have no gravitational force? double distance = ¼ gravitational force quadruple distance = 1/16 gravitational force double mass = double force double both masses = quadruple force

What happens to FG if the distance is cut in half? Example Problem 1: What is the gravitational force between tow dogs, 5 kg and 7 kg that are 2 meters apart? G = 6.67 x 10-11 r = 2 m  m1 = 5 kg m2 = 7 kg F = ?

What planet would you most want to visit What planet would you most want to visit? Does it have more or less gravity than the earth? F = 20.5 N