9/30/13, Monday

Post date: Sep 30, 2013 3:33:30 PM

Bell ringer

• • How grippy is your shoe? Find the coefficient of static friction between your shoe and a wooden meter stick by measuring the weight of your shoe and the angle the meter stick makes with the ground when your shoe starts to slide down the meter stick.

Activities

• • Correct chapter 4 homework

  • Questions about homework?

  • Fundamental forces of nature notes

    • Gravity

      • Attractive force that exists between all objects with mass

      • Strength depends on masses of two objects and distance between them

      • Weakest of the forces

• • • Electromagnetic force

      • Attractive or repulsive force caused by charges, magnetic poles (opposites attract, likes repel)

      • Strength depends on amount of charges (or strength of magnetic field), distance between them

• • • Strong nuclear force

      • Force that acts only over tiny distances to bind protons and neutrons together in the nucleus of atoms

      • Attractive force over very small distances, strongly repulsive over even smaller distances (keeps particles close, but not TOO close)

• • • Weak nuclear force

      • changes the flavor of quarks

        • Quarks - subatomic particles that make up larger particles.

          • 6 types (flavors) of quarks - up, down, top, bottom, strange, and charm

          • different combinations of quarks make up larger particles (neutron = 1 up and 2 down quarks, proton = 2 ups and 1 down quark)

        • flavor changes mean transformations from one type of particle to another (e.g. if one of the down quarks in a neutron changed to an up quark, you would have a proton instead of a neutron)

      • As particle change, sometimes unstable nuclei are created, which then break into smaller pieces in a process called fission (particles ejected = radiation)

Assignments

• • P.145-149: 9, 10, 19, 20, 22, 31, 35, 38, 48, 50 (due Today)

Announcements

• • Chapter 4 test Tuesday

  • Air resistance lab due Tuesday