Chapter 8 Notes Motion and Forces

Chapter 8.1 Notes Speed: distance traveled divided by the time interval during which the motion occurred Speed=Distance/time Constant speed: speed does not change

Velocity: is a quantity describing both speed and direction (same number as speed but with a direction added) Momentum: a quantity defined as the product of an objects mass and its velocity Momentum = Mass x Velocity

Chapter 8.2 Notes Acceleration change in velocity, if the object speeds up, slows down, changes direction. Acceleration = Final velocity - initial velocity time

Force the cause of acceleration, or change in an object’s velocity. Balanced forces are forces acting on an object that combine to produce a net force equal to ZERO. Unbalanced forces are forces acting on an object that combine to produce a net nonzero force.

Friction the force between two objects that opposes the motion of either object. So whenever two objects touch there is friction. Air resistance is a type of friction. Low friction shoes on ICE High friction shoes on pavement

Gravity- the attraction between two particles of matter due to their mass. The larger the mass the larger the gravitational pull. The closer together the two objects are the greater the gravitational pull.

Chapter 8.3 Notes Newton’s 3 Laws of Motion 1.An object at rest remains at rest and an object in motion maintains its velocity unless it experiences an unbalanced force. 2.The unbalanced force action on an object equals the object’s mass times its acceleration. Force= (m)(a) 3.For every action force, there is an equal and opposite reaction force.

Newton’s 1 st law Inertia the tendency of an object to remain at rest or in motion with a constant velocity. That is why we wear seatbelts, put babies in car seats, need to sit away from airbags.  New York State passed the first seat belt law in the US in 1984 under the leadership of John D. States, an orthopedic surgeon who dedicated his career to improving automotive safety. John D. States

Remember, it is not just the law, but a way to help prevent accidental injury or death when your children are riding in a vehicle. These laws are the minimum requirements. Children are safer riding in booster seats through 80 pounds than using the vehicle's seats and restraint systems designed for adults. Many states are seeking to change their laws to require children stay in restraints through 8 years and 80 pounds.

Newton’s 2 nd law Free fall is when the force of gravity is the only force action on an object. Gravity (g) = 9.8 m/s 2 Weight = mass times gravity Terminal velocity is the maximum velocity reached by a falling object.

Weight is the pull of gravity on an object…changes from place to place. Mass is the amount of matter in an object…NEVER changes.

How Fast do Rockets Go?? Flight PlanSpeed Required Earth to LEO (low Earth orbit)17,000 mph Earth to Earth escape24,200 mph Earth to lunar orbit25,700 mph Earth to GEO (geosynchronous Earth orbit) 26,400 mph Earth to solar escape36,500 mph Rockets deal with Newton’s 3 rd law of motion…

Work Cited “Sonic Boom Plane”. April 7, e_navy.jpg e_navy.jpg “US map of car seat law and info”. April 9, “Seat belt laws”. April 9, “rocket info.” April 9, cs/Propulsion/2-how-fast-conventional.html cs/Propulsion/2-how-fast-conventional.html