Simple Machines - PowerPoint PPT Presentation

Loading...

PPT – Simple Machines PowerPoint presentation | free to download - id: 78a962-N2VhN



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Simple Machines

Description:

Simple Machines Device that makes doing work easier is a machine Machines increase applied force and/or change direction of applied force to make work easier Effort ... – PowerPoint PPT presentation

Number of Views:69
Avg rating:3.0/5.0
Slides: 22
Provided by: Mesq1
Learn more at: http://www.midlandisd.net
Category:
Tags: machines | simple

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Simple Machines


1
(No Transcript)
2
Simple Machines
  • Device that makes doing work easier is a machine
  • Machines increase applied force and/or change
    direction of applied force to make work easier

3
Effort and Resistance
  • Force applied to machine is effort force
  • Resistance force force applied by machine to
    overcome resistance

4
Energy and Simple Machines
  • Amount of energy the machine transfers to the
    object cannot be greater than the amount of
    energy transferred to the machine

5
Energy and Simple Machines
  • An ideal machine with no friction would have the
    same input work and output work
  • Some energy transferred is changed to heat due to
    friction

6
Mechanical Advantage
  • The number of times a machine multiplies the
    effort force.

7
Efficiency
  • Measure of how much of the work put into a
    machine is changed into useful output work by the
    machine.

8
Lever
  • Bar that is free to pivot about a fixed point
    called the fulcrum
  • MA of lever
  • depends on the
  • placement of
  • the fulcrum

9
Simple Machines
Which lever will allow the weight to be lifted
with the least amount of force?
It is easier to lift a weight when the fulcrum is
closer to the weight being lifted.
10
Simple Machines
Below is a picture of a perfectly balanced
system. Describe how mass affects the distance
from the fulcrum.
200 g
100 g
The greater mass is closer to the fulcrum.
Notice that is twice as big and half as close. We
always measure to the center of mass.
11
Pulley
  • Grooved wheel with a rope or cable running along
    a groove

The greater the number of times the cable wraps
around the pulleys, the greater the MA.
12
Simple Machines
Which pulley system will allow the weight to be
lifted with the least amount of force?
Moveable pulleys, often grouped together in block
and tackle systems, reduce the amount of force
needed to lift an object.
Block and Tackle
13
Wheel and axle
  • Machine with two wheels of different sizes
    rotating together

14
Simple Machines
Gears are a type of simple machine. While it
takes less force to spin the larger wheel, the
smaller wheel spins at a faster rate.
15
Inclined Plane
  • Sloping surface that reduces the amount of force
    required to do work

16
Simple Machines
Which ramp would it be easiest to slide a box up
to the given height?
Making ramps longer lowers the amount of force
needed to move an object up the ramp.
17
Wedge
  • Inclined plane with one or two sloping sides

18
Screw
  • Inclined plane wrapped in a spiral around a
    cylindrical post

19
Compound machine
  • Uses a combination of two or more simple machines

20
Efficiency
The efficiency of machines can be determined by
using a simple formula found on the formula chart.
Machines are always less than 100 efficient
because of the force that opposes motion between
the parts of the machine. What force is it that
opposes this motion?
Friction opposes the motion in the machines.
Friction converts the machines work into heat.
21
Formulas
Vf Vi at d Vi t ½ at2 2ad Vf2
Vi2 d ½ (Vf Vi) t
W F x d
P Work/t
KE ½mv2
GPE mgh
ME KE PE
About PowerShow.com