Section 1 Laws of Motion p. 346 Chapter 11 Forces Section 1 Laws of Motion p. 346

Observe effects of 1st two laws of motion Objectives Observe effects of 1st two laws of motion Calculate the gravitational pull of an object and its altitude based on falling time

I. Newton’s First Law - Inertia A. Inertia- tendency for an object in motion to stay in motion and an object at rest to stay at rest unless acted upon by some outside unbalanced force B. Inertia is directly related to mass II. Newton’s Second Law A. Force is equal to mass times acceleration F=ma B. Measured in Newtons = 1 kg x 1 m/s2 = 1 N

Chapter 11 Forces Section 2 Gravity p. 352

I. Universal Gravitation Equation F= G(m1m2/d2) A. All matter is affected and exerts gravity A Gravity Demonstration B. Gravity increases as mass increases C. Gravity decreases as distance increases Blue Angels II. Free Fall and Weight Weightlessness Free fall- when gravity is the only force acting on an object A. Gravitational acceleration constant on Earth is 9.8 m/s2 = g

B. Weight equals mass times free fall acceleration 1. Weight = mass x free-fall acceleration or w=mg 2. In space, you appear weightless because everything is accelerating (falling) at the same rate (apparent weightlessness) C. Weight and mass are different (moon = g = 1.6 m/s2) Galileo’s Laws of Falling Bodies (p27) Feather & Hammer Drop

D. Weight influences shape E. Velocity is constant when air resistance balances Terminal Velocity- no longer accelerating because gravity is balanced by air resistance F. Orbiting- combination of free fall and forward motion III. Projectile Motion- curved path of an object with force applied behind it on or near gravity (e.g.- orbit) One motion does not affect the other