p. 105 Work and Simple Machines 7th Grade ISN
Objective: I will define work and power.
Use words and/or illustrations to define work and power.
How Powerful Am I?
Force
Weight (N) X Distance
_________ X
X # of trips up stairs = Work (J)
/ time=
power (W)
_______m X ___________ trips = _________Joules / 60 s = ________ W
Directions for How Powerful Am I?:
1.
2.
3.
4.
5.
Multiply your weight in pounds by 4.45 to get your weight in N. Record this number where it says Force Weight (N).
Record distance up the stairs outside of room 212 as
Form 2 lines at the bottom of stairs outside of this classroom. The first person in each line counts how many trips up the stairs they
make in one minute. The 2nd person in line is the timer. NO SKIPPING STAIRS! BE SAFE!! IT IS NOT A RACE!!! Record the # of trips
you made up the stairs in 60 seconds after the timer says stop. Go to the back of the line.
The timer now become takes a turn going up and down the stairs in one minute and the next person in line is now the timer.
Repeat this process until everyone has traveled the stairs. Both lines at the bottom of the stairs can participate at the same time.
To determine the amount of power you have, multiple your force in N times the distance up the stairs times the number of trips ,
then divide by 60. This is how many Watts of power you produced while doing work by going up and down the stairs.
p. 106 Work and Simple Machines 7th Grade ISN
Work and Power Notes p 406-411
• Work = Force (N) X Distance (m)
Measured in Joules (J)
1 Newton meter = 1 Joule (J)
3 Conditions needed for something to be considered as work
1. Force
2. Motion
3. Force and motion must be in the same direction
• Power-- The rate at which work is done.
• Power = Work
Time
• Measured in Watts (W)
or
Force X Distance
Time
p.103 Work and Simple Machines 7th Grade ISN
Objective: I will identify the 6 types of simple machines.
Cut apart the images into squares. Put each object into a group.
You must include at least 3 groups. Glue images in groups here.
Name each group according to how you classified them.
Identify each image glued here as a type of simple machine:
lever (L), wheel and axle (WA), screw (S), inclined plane/ramp (I),
wedge (W), pulley (P)
p. 104 Work and Simple Machines 7th Grade ISN
Simple machine Notes--Foldable
Types of Simple Machines
p. 105 Work and Simple Machines 7th Grade ISN
Objective: I will identify how simple machines make work easier.
Use a complete sentence to answer the following sentence:
Why are simple machines used?
Use words and/or illustrations to explain the following: Suppose
you make a seesaw with a movable pivot point. You want to use it
with a younger friend who weighs half what you weigh. If you and
your friend want to sit on the two ends of the seesaw, where
should you position the fulcrum (pivot point)?
p. 106 Work and Simple Machines 7th Grade ISN
Machine—device that allows you to do work in a way that is easier or more
effective.
Ways machines make work easier:
1. Changes the amount of force you exert, changes distance over which you exert
your force, or changes the direction in which you exert the force
2. Multiplies either force or distance
a) Input force —force you exert on a machine
b) Output force —force exerted by the machine
c) Mechanical advantage (M.A.)—number of times a machine increases a
force exerted on it; no units to label
1. M.A. = output force
input force
2. Ideal M.A. – mechanical advantage of a machine when all other forces
are not considered; this # is always greater than M.A.
• Lever – length of input or effort arm/ length of output or resistance arm
• Inclined plane/ramp = length of ramp / height of ramp
• Pulley– equal to the number of sections of rope that support object
• Wheel & axle– radius of wheel / radius of axle
d) input work– input force multiplied by the input distance
e) output work – output force multiplied by the distance
p. 107 Energy 7th Grade ISN
Objective: I will identify and define different types of energy.
Draw a representation of energy.
Complete the jumping frog activity. Draw your frog here and explain how it transfers
potential energy to kinetic energy.
p. 108 Energy 7th Grade ISN
Types of Energy Notes
Potential & Kinetic
Energy
1. Potential Energy---stored energy
a) Gravitational potential energy—energy stored due to height
1. Calculated: (weight) (height)
b) Elastic potential energy—energy stored due to elasticity of material
c) Can be increased by increasing mass or height
2. Kinetic energy —energy in motion
a) Calculated-- mass X velocity2
2
b) Can be increased by increasing mass or speed