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Newton’s Second Law . Section 3-1. Force and Acceleration . The greater the force is that is applied to an object, the greater its acceleration. F=ma Hi there from DerekAlan Kreutzfeldt. Force and Mass. The acceleration of an object depends on its mass as well as the force exerted on it
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Newton’s Second Law Section 3-1
Force and Acceleration • The greater the force is that is applied to an object, the greater its acceleration. • F=ma • Hi there from DerekAlan Kreutzfeldt
Force and Mass • The acceleration of an object depends on its mass as well as the force exerted on it • Throw a baseball and a softball • F=ma
Newton’s Second Law • F = m a • The net force acting on an object causes the object to accelerate in the direction of the force. • Force will be labeled in Newtons (N) • Mass = kg • Acceleration = m/s2
You are pushing a friend on a sled. You push with a force of 40 newtons. Your friend and the sled together have a mass of 80kg. What is the acceleration of your friend on the sled?
A tennis ball undergoes an acceleration of 5,500m/s2. How much force would the tennis racket have to exert to give the ball this acceleration? The ball has a mass of .06kg.
Friction • Force that opposes motion between two surfaces that are touching. • What happens to a skate board after you give it a push? • Why does it slow down and eventually stop? • Would the type of surface make a difference?
Amount of Friction • The amount of friction depends on two things. • Kinds of surfaces • Force pressing the surfaces together
Three types of Friction • Static Friction • Sliding Friction • Rolling Friction
Static Friction • The friction between 2 surfaces that are not moving past each other. • Getting the object moving
Sliding Friction • Force that opposes the motion of two surfaces sliding past each other. • Once you have the object moving, there is still friction.
Rolling Friction • The friction between a rolling object and the surface it rolls on. • Put sand on the ice when your car is stuck. • Usually much less than static or sliding friction.
Air Resistance • Force that acts in the opposite direction to that of the object’s motion. • Crumpled paper VS Flat paper • Surface Area • Air Resistance depends on: • Speed • Size • Shape of object
Terminal Velocity • The highest velocity that a falling object can reach. • The point where the forces acting on the object are balanced.