Calculating Force and Types of Friction Forces Calculating Force and Types of Friction

Force: A push or pull exerted on an object A force is described by its strength and by the direction in which it acts SI Unit of Force = newton (N) Sir Isaac Newton

Net Force: Sum of all forces acting on an object The change in motion of an object is determined by the net force You can find the net force by adding together the strengths of all the individual forces Any nonzero net force causes a change in motion

Calculating Net Force: Example: 2 forces pushing on an object from the right Net Force = 8N moving the box to the Right 5N 3N 8N

What is the net force for each situation? State whether the forces are Balanced or Unbalanced

What about this situation? Balanced Forces: result in no movement of the object Unbalanced Forces: the object will move in the direction with the larger applied force

Friction acts in the direction opposite of the object’s motion Friction: The force that two surfaces exert on each other when they rub together Two factors that affect the force of friction 1. The surfaces involved 2. How hard the surfaces are pushed together Smooth surfaces produce less friction Friction acts in the direction opposite of the object’s motion

Types of Friction Sliding: when 2 solid surfaces slide over each other * Makes moving objects slow down or stop Static: acts on objects that are NOT moving * Force that keeps you from moving Fluid: when a solid object moves through Water or Air Rolling: occurs when an object Rolls across a surface

Gravity: the force that acts to pull objects straight down toward the center of the earth Universal Gravitation: states that ALL objects are attracted to each other 2 factors that affect Gravitational Attraction * Mass and the Distance between the objects The greater the mass, the great the gravitational force As distance increases, gravitational force decreases

Calculating Force: Force = mass X acceleration F = ma Force = mass X acceleration This formula calculates the amount of force that must be applied to an object to accelerate it