Bell Ringer

word energy? (List at least three items in your Bell

do work?

(J)
Types of energy include:
Mechanical: Energy of movement and position
Chemical: Energy

Energy produced from the splitting of atoms
Radiant Energy: Energy traveling

energy
Factors affecting work done:
The application of a force
The movement of

object 2m high?

J = 1 N.m
Note that work requires a distance

do work?
You push a stationary wall with a force of

= Work / Time
P = W/t
Units: Watts (W) where 1

1 hp  750 W

a single bound, how much does Superman perform?
If this occurs

depend on the path taken
Work depends only on the object’s

clock
Raising the arm on a pile driver
All of these objects

major types of mechanical energy:
Potential Energy: Energy of position
Kinetic Energy:

= mass x gravity x height
P.E. = mgh
Recall: weight =

= ½.mass.velocity2
KE = ½mv2

squared when determining KE
If the velocity of the object is

of Energy: Energy cannot be created or destroyed, only changed

and forth
Most of the time during this transformation, some energy

a mass of 60kg, what is her kinetic energy?
If Bob,

object is equal to the amount of work needed to

to the work the object is capable of doing while

general Work-Energy Theorem:
If no change in energy occurs, then no

of simple machines.

to change the directions of forces
There are six types of

support to assist in lifting or moving an object
Wedge: An

level to a higher level
Screw: An inclined plane wrapped around

to input force
Mechanical Advantage = Output Force

i.e. A machine which outputs 80 N for every 10 N you put in has a mechanical advantage of 8.
Note that the load will move only 1/8 of the input distance

total work input


Efficiency = Useful Work Output

Efficiency is expressed as a percent
i.e.) An efficiency result of 0.25 means 25% efficiency

the energy put into the machine exits as useful energy
All

rope or cable
System of pulleys:
Multiplies input forces, creating large

the weight
Tension in this cable is the same throughout

Mechanical advantage here equal to?
What is the input force required

to lift the load?
For every 2 meters the rope is

a fixed point
Fulcrum: The pivot point of a lever
Change the

input force and the load
i.e.) A seesaw
Type 2 Lever: The

between the fulcrum and the load
i.e.) Your forearm pivoting about

Output
or
(Fd)input = (Fd)output
Therefore: A small input force over a large

a sharp edge which separates or cuts materials apart
i.e. knife

through its center which lifts or moves objects
ie: Cart

to a higher level
i.e. Accessibility ramp

objects together or lifts materials

a task
Examples?
Rube Goldberg Device

kg mass 3m?
What is the work energy theorem?