Force and Motion PHYSICS HONORS Lecture Notes Laws

Force and Motion PHYSICS HONORS Lecture Notes Laws of Motion (Chapter 4) 2048

Forces Types Range Size Gravitational Unlimited 100 Electromagnetic Unlimited 106 Weak Nuclear 10 -12 m 1020 Strong Nuclear 10 -15 m 1035 Laws of Motion (Chapter 4) 2048. ppt

Newton’s First Law (Law of Inertia) If no external force acts, an object maintains a constant velocity. Laws of Motion (Chapter 4) 2048. ppt

Mass Gravitational mass mg Inertial mass mi mg = m i Laws of Motion (Chapter 4) 2048. ppt

Newton’s Second Law Units of Force System SI British Mass kg slug Acceleration Force m/s 2 N = kg m/s 2 ft/s 2 lb = slug ft/s 2 Laws of Motion (Chapter 4) 2048. ppt

Force of Gravity and Weight T 2 m FN Fg Fg = mg Weight= mg Laws of Motion (Chapter 4) 2048. ppt

Newton’s Third Law F 2 F 1 Action/Reaction Forces

Applications of Newton’s Laws Find Tensions T 1 and T 2 q T 1 sin(60) T 1 T 2 T 1 cos(60) mg m q = 60 o m = 20 kg Laws of Motn (Chapter 4) 2048. ppt

Applications of Newton’s Laws Another method q T 1 mg q T 1 T 2 mg m Laws of Motion (Chapter 4) 2048. ppt

Applications of Newton’s Laws vo= 0 F Dt = 5 s v= ? F = 20 N m = 5 kg m Find velocity of block after Dt Laws of Motion (Chapter 4) 2048. ppt

Applications of Newton’s Laws vo= 20 m/s F v= 0 F = 10 N m = 5 kg m d Find distance block moves Laws of Motion (Chapter 4) 2053. ppt

Forces on m 1 N m 1 T m 1 g m 2 T m 2 g Forces on m 2 Laws of Motion (Chapter 4) 2053. ppt

Mass 1 T Mass 2 T m 2 m 1 g m 2 g Laws of Motion (Chapter 4) 2053. ppt

Frictionless incline y N mg sin(q) mg cos(q) x q mg q Laws of Motion (Chapter 4) 2053. ppt

m 1 T T m 1 g sin(q 1) q 1 m 1 g m 2 m 2 g sin(q 2) q 2 Laws of Motion (Chapter 4) 2053. ppt

Friction: Force of Static Friction N fs m F mg Laws of Motion (Chapter 4) 2053. ppt

Friction: Force of Kinetic Friction fk v N F m mg Laws of Motion (Chapter 4) 2053. ppt

Table 5. 2 Coefficients Of Friction Steel on steel Aluminum on steel Copper on steel Rubber on concrete Wood on wood Glass on glass Waxed wood on wet snow Waxed wood on dry snow Metal on metal (lubricated) Ice on ice Teflon on Teflon 0. 74 0. 61 0. 53 1. 0 0. 25 -0. 5 0. 94 0. 14 -----0. 15 0. 1 0. 04 0. 57 0. 47 0. 36 0. 8 0. 2 0. 4 0. 1 0. 04 0. 06 0. 03 0. 04 Laws of Motion (Chapter 4) 2053. ppt

y N a fk mg sin(q) mg cos(q) q x mg q Acceleration on a rough incline Laws of Motion (Chapter 4) 2053. ppt

Rough surface N T fk m 1 g T m 2 g Laws of Motion (Chapter 4) 2053. ppt

Three mass system - find acceleration m 2 m 3 m F Laws of Motion (Chapter 4) 2053. ppt

Three mass system - find T 2 m 2 m T 2 3 m F Laws of Motion (Chapter 4) 2053. ppt

Three mass system - find T 1 m T 1 2 m T 2 3 m F Laws of Motion (Chapter 4) 2053. ppt

Pulling a block with constant speed N mk f F q m mg y N F q f x mg The normal force Laws of Motion (Chapter 4) 2053. ppt

Pulling a block with constant speed N mk f F q m mg y N F q f x mg The frictional force Laws of Motion (Chapter 4) 2053. ppt

Pulling a block with constant speed N mk f q m y F mg N F q f x mg The coefficient of friction Laws of Motion (Chapter 4) 2053. ppt

m = 200 kg ms = 0. 500 vo= 20 m/s Crate on truck Truck’s maximum deceleration Laws of Motion (Chapter 4) 2053. ppt

mg cosq q Frictionless A block is released from rest N at the top of an incline. Find the final speed and the mg d sin time to side to the bottom. q mg q Laws of Motion (Chapter 4) 2053. ppt

f = mk. N = mkmg cosq N f mg cosq With friction q mg d sin q A block is released from rest at the top of an incline. Find the final speed and the time to side to the bottom. mg q Laws of Motion (Chapter 4) 2053. ppt

Force and Motion END Laws of Motion (Chapter 4) 2053. ppt