Physical SciencePhysical ScienceForcesForces

Section 3.1Section 3.1Standard-Standard-

SPS8. Students will determine relationships among SPS8. Students will determine relationships among force, mass, and motion. force, mass, and motion.

a. Calculate velocity and acceleration. a. Calculate velocity and acceleration. b. Apply Newton’s three laws to everyday situations b. Apply Newton’s three laws to everyday situations

Essential Questions: 1. How are force, mass, and motion Essential Questions: 1. How are force, mass, and motion related?related?

2. What is Newton’s Second Law?2. What is Newton’s Second Law?

Forces

Newton’s Second LawNewton’s Second Law Force and motion are Force and motion are relatedrelated

– An object will have greater An object will have greater accelerationacceleration if if a greater force is applied to ita greater force is applied to it

– The The massmass of an object and the force of an object and the force applied to it affect accelerationapplied to it affect acceleration

Newton’s second law of motion- Newton’s second law of motion- connects force, mass, and acceleration connects force, mass, and acceleration in the equation acceleration equals net in the equation acceleration equals net force force divided bydivided by mass mass– F = m x a or a = F/m F = m x a or a = F/m

Newton’s Second LawNewton’s Second Law FrictionFriction- force that opposes motion between two - force that opposes motion between two

surfaces that are touching each othersurfaces that are touching each other Microwelds- Microwelds- areas where surfaces stick together- areas where surfaces stick together-

the source of frictionthe source of friction Friction between two surfaces that are not Friction between two surfaces that are not

moving past each other is called moving past each other is called static static frictionfriction Sliding Sliding friction- force that opposes the motion of friction- force that opposes the motion of

two surfaces sliding past each othertwo surfaces sliding past each other Friction between a rolling object and the surface Friction between a rolling object and the surface

it rolls on is calledit rolls on is called rolling rolling frictionfriction

Newton’s Second LawNewton’s Second Law Air resistanceAir resistance- the force that opposes - the force that opposes

the force of gravitythe force of gravity The The amountamount of air resistance depends of air resistance depends

on an object’s shape, size, and speedon an object’s shape, size, and speed Terminal velocity-Terminal velocity- forces on a falling forces on a falling

object are balanced and the object object are balanced and the object falls with constant speedfalls with constant speed

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/mmedia/newtlaws/efar.html http://www.glenbrook.k12.il.us/GBSSCI/PHYS/mmedia/newtlaws/sd.html