Velocity and Acceleration
Velocity and Acceleration
vocabulary words:
Force, motion, reference point, speed, velocity, and acceleration
The difference between speed and velocity is that velocity has a direction add to speed.
Speed = 55mph Velocity = 55mph north
Formulas:
Speed = distance
time
Acceleration = final velocity – start velocity
Time
Examples of changing acceleration:
Someone jogging at 5mph along a winding road
Driving to school on Harmony Grove Church or Dabbs Bridge Road due to it being winding roads.
Balanced and Unbalanced forces
Vocabulary words:
Balanced force, unbalanced force, net force, mass, inertia, friction, gravity
How do forces slow an object down? Force causing an object to slow down is greater than the force trying to push or pull it forward
What would happen to an object that is already moving and you add to the net force already acting on the object? It will speed up due to it is already moving and you are add to that force in the same direction.
Gravity
Depends on the mass of an object and the distance between them.
Pulls on all objects 9.28m/s2
When would a pair of objects have the least gravitational attraction to each other?
When they are farthest apart from each other.
Inertia is affected by the mass of an object. The larger the mass the more inertia it will take to get it to move or to make it stop. (Think of a train and a small car, the train will take over a mile to stop and the car a few 100ft)
Simple Machines
Vocabulary words:
Work, machine, inclined plane, wedge, screw, lever, pulley, wheel and axle
Be able to identify each type of simple machine
Pulley example: hoisting(pulling) a flag up a flag pole
Inclined plane example: wedge and a screw
Wedge example: Axe blade and the handle acts as a lever that changes the input force.
Zippers are also wedges
Levers example: 1st class - scissors, pliers, a seesaw 2nd class- bottle openers, wheel barrows
3rd class – hockey stick, fishing pole, and baseball bats
Your arm lifting a weight is also a 3rd class lever.
Screw example: Lid on a jar or bottle of soda, screw used in building of a deck on a house.
(a screw is a inclined plane wrapped around a cylinder)
Wheel and Axle example: a wheel on a car and the axle that it is attached to as well, door knob, and a cars steering wheel.
Formula for work:
Work = force x distance or W = F x D
Levers – three different types and give examples of each type
F =fulcrum 1 (middle of 1st class)
R = resistance or load 2 (middle of 2nd class)
E = effort or force applied to lift the load 3 (middle of 3rd class)
(Spells free to help your remember where each is located)
mechanical advantage of a leverisincreasedwhen either the effort(or force) is moved further away from the fulcrum or the load is shifted closer to the fulcrum, or both.
Mechanical Advantage formula:
Mechanical Advantage = Resistance
Effort
Mechanical Advantage is the number of times a machine multiplies the force. (or the number of times a machine decreases the effort force required to move an object.
Study the graphs note sheet given to you in class.
What 2 forces act on an object that is falling? Gravity and air resistance
How does friction affect the movement of an object? Less friction will allow the object to move easier and possibly faster, more friction will cause the object to slow down or hard to move.
Newton’s 3 Laws of motion
1st– an object in motion will stay in motion and an object at rest will stay at rest unless acted upon by an outside force (inertia is being described) ex: riding in a car and you hit the brakes hard, you fly forward
2nd - Force = mass x acceleration - the mass of an object will affect the force needed to move the object. (Heavier the object the more force need to move it)
3rd - For every action there is an equal and opposite reaction force. Ex: rocket lifting off into space.
Also study all of your notes!!!
Quizlet for vocabulary!
I also posted on the website other resources to help you study for the test!!!!