IPC FINAL

frame of reference

a system of objects that are not moving with respect to one another

relative motion

movement in relation to a frame of reference

distance

The length of a path between two points

SI unit for distance

meter (m)

Displacement

Distance and direction of an object's change in position from the starting point to the end point

Vector

A quantity that has magnitude and direction

resulant vector

the vector sum of two or more vectors

speed

The distance an object travels per unit of time

SI unit for speed

m/s

average speed

total distance divided by total time

instantaneous speed

the speed of an object at one instant of time

d = vt

distance = total time x average speed

constant high speed

constant low speed

Varying Speed

Velocity

speed and direction of motion

Acceleration

The rate at which velocity changes

What can acceleration be?

speeding up, slowing down or changing direction.

free fall acceleration

the movement of an object toward Earth solely because of gravity

constant acceleration

a steady change in velocity

Vf-Vi = at

change in velocity = acceleration x total time

Force

a push or pull on an object

What can a force do?

a resting object to move, or it can accelerate a movie object by changing the objects speed or direction

SI unit for force

Newton (N)

net force

The combination of all forces acting on an object

balanced forces

forces acting on an object that combine and form a net force of zero

unbalanced forces

object accelerates

4 main types of friction

static, sliding, rolling, fluid

static friction

Friction that acts on objects that are not moving

sliding friction

friction that occurs when one solid surface slides over another

rolling friction

friction that occurs when an object rolls over a surface

fluid friction

friction that occurs as an object moves through a fluid

air resistance

Fluid friction acting on an object moving through the air

Gravity

force that acts between any two objects

how does earth gravity act?

downward and towards the center of earth

Gravity causes objects to…

accelerate downward

how does air resistance act?

the direction opposite to the motion and reduces acceleration

terminal velocity

the constant velocity of a falling object when the force of air resistance is equals the force of gravity

projectile motion

the curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth

what causes a curved path?

combination of forward velocity and downward force of gravity

Aristole

Greek philosopher and scientist that made discoveries through careful observations and logical reasoning

Galileo

Italian scientist. rolled balls down wooden ramps & studied how gravity produces constant acceleration.

Newton

made the laws of motion

Newton's first law of motion

an object in motion will remain in motion unless acted upon by another force

Newton's Second Law of Motion

The acceleration of an object depends on the mass of the object and the amount of force applied.

F = ma

Force = mass x acceleration

Weight

A measure of the force of gravity on an object

W= mg

weight= mass x acceleration due to gravity

gravity (g)

9.8 m/s ^2

Mass

A measure of the amount of matter in an object

Newton's Third Law of Motion

if one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object.

mg * m/s = mv

momentum = mass x velocity

2 forces that can attract and repel

electric and magnetic forces

Newton's Law of universal gravitation

Every object in the universe attracts every other object

work

the product of force and distance

no movement means

no work

for force to do work on a object it must do what ?

the force must act in the same direction as the object moves

What does work depend on?

direction

W = Fd

work = force x distance

SI unit of work

Joule (J)

Power

the rate at which work is done

W = Pt

Work done = power x time

SI unit for power

Watt (W)

input force

the force exerted on a machine

input distance

the distance the input force acts through

work input

the work done by the input force acting through the input distance

output force

the force exerted on an object by a machine

output distance

the distance the output force is exerted through

work output

the output force multiplied by the output distance

Mechnical Advantage

the number of times a machine increases a force exerted on it

actual machanical advantage

(AMA) equals the ratio of the output force to the input force

AMA equation

output force/input force

ideal mechanical advantage

the mechanical advantage of a machine in the absence of friction

IMA is always…

Greater than the AMA

IMA equation

input distance/output distance

Efficiency

The percentage of the input work that is converted to output work

Efficiency can never..

100%

Efficiency equation

work output/work input x 100%

6 types of simple machines

lever, wheel and axle, inclined plane, wedge, screw, pulley

lever

A rigid bar that is free to move around a fixed point

fulcrum

The fixed point around which a lever pivots

input arm

the distance between the input force and the fulcrum

output arm

the distance between the output force and the fulcrum

IMA of a lever

input arm/output arm

first class levers

seesaw, scissors, pliers

second class levers

wheelbarrow

third class levers

baseball bat, shovel, fishing pole

wheel and axle

a simple machine consisting of two circular objects of different sizes; the wheel is the larger of the two circular objects

IMA of wheel and axle

radius of wheel/radius of axle

inclined plane

a slanted surface along which a force moves an object to a different elevation

IMA of inclined plane

Distance/ Change in Height

wedge

V-shaped object whose sides are two inclined planes sloped toward each other

screw

An inclined plane wrapped around a cylinder

Pulleys

a simple machine that has a grooved wheel that holds a rope or a cable

fixed pulley

A pulley that is attached to a structure

movable pulley

pulley attached to object lifted; reduces force, but doesn't change its direction

pulley system

A combination of fixed and movable pulleys

compound machine

a combination of two or more simple machines that operate together

Energy

the ability to do work

What is work?

transfer of energy