What role do forces play in the world around us? Wednesday November 4, 2015 Unit Question What role do forces play in the world around us? Guiding Question / Learning Target How do Newton’s Laws affect everyday objects? Warm-up Which of Newton’s Laws is responsible for this situation? Agenda Forces Notes and Diagrams Ramp Demonstration Homework Quiz Friday 1st Law: An object in motion stays in motion

What is a Force? Force – push or pull one body exerts on another

What is a Force? Force is measured using the standard metric unit known as the Newton (N). One Newton is the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s. Thus, the following unit equivalency can be stated: 1 Newton = 1 kg • m/s2

A force is a vector quantity.  A vector quantity is a quantity that has both magnitude (size) and direction.

Net force – the combining of forces when two or more forces act on an object

Balanced forces – forces that are equal in size and opposite in direction Forces are acting on the same object Do not cause the motion of the object to change

Unbalanced forces – forces that are not equal and/ or opposite in direction Net force causes object to move in direction of force Unbalanced Balanced

How does the rocket fly? Unbalanced Forces!

How are these not balanced forces? Because the object is moving!

Common Forces Gravity – the attraction two objects have for one another Air resistance – opposing force an object feels when traveling through air Friction – resistance to motion caused by two objects in contact with one another.

Exit Question Which way will this block move?

Newton’s Labs Go to your assigned station. Do not move until instructed to do so.

Inertia and Mass Inertia – the tendency of an object to resist changes in its motion The greater the mass of an object the greater its inertia Newton’s First Law of Motion – ‘Stuff keeps doin’ what its doin’ until somethin’ else messes with it…’

Check it out… http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/Newton1/The_Net_Force.html#NetForceQuiz

F = m x a Force, mass, and acceleration are all connected. For any object, the greater the force applied to it, the greater its acceleration will be.

Learning Checkpoint If two equal forces act on an object in opposite directions, what is the acceleration? According to balanced forces, the acceleration of the object would be zero.

Learning Checkpoint Calculate the force on an object that has a mass of 12 kg and an acceleration of 4 m/s/s. F = m x a F = 12 kg x 4 m/s/s F = 48 kg x m/s/s = 48 N

Learning Checkpoint What is the acceleration of a 200 kg object with 3,000 N of net force acting on it? a = F / m a = 3,000 kg x m/s/s / 200 kg a = 15 m/s/s

Newton’s Third Law When one object exerts a force on a second object, the second one exerts a force on the first that is equal in size and opposite in direction. “To every action, there is an equal and opposite reaction.” Example – when you jump on a trampoline the trampoline exerts the same force on you in the opposite direction.

Learning Checkpoint When a force is exerted on a box, an equal and opposite force is exerted by the box. These forces are known as _____ forces. These forces are action-reaction forces.

What is the difference between weight and mass? Learning Checkpoint What is the difference between weight and mass? Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity on the object’s matter.