1a. Define: Simple machine
A device that either multiplies or redirects a force
1b. Define: Force
A push or pull exerted on an object in an effort to change that object’s velocity
1c. Define: Mechanical advantage
The amount by which force or motion is magnified in a simple machine
1d. Define: Diameter
The length of a straight line that travels from one side of a circle to another and passes through the center of the circle
1e. Define: Circumference
The distance around a circle, equal to 3.1416 times the circle’s diameter
- How is applied science different from science?
motive
- What gives rise to technology?
accident, science or applied science
- Identify each of the following as a science experiment or an applied science experiment:
a. An experiment to determine how to make electronic circuits smaller
b. An experiment to understand what factors affect how electricity runs in an electronic circuit
c. An experiment to figure out how to reduce electronic noise in an electronic circuit
d. An experiment to figure out the speed of electrons as they flow through an electronic circuit
a & c are applied science experiments because the goal is to make something better
b & d are science experiments because the goal is to learn something
- Which of the following would be considered technology?
a. A classification scheme for all animals
b. A vaccination that will keep all animals from contracting the flu
c. A new diet for dogs that will lead to longer life
d. An understanding of what causes urinary-tract infections in cats
b & c are technology
- LIst the 6 types of simple machines
lever, pulley, wheel & axle, inclined plane, wedge and screw
- Which 2 simple machines look identical?
inclined plane & single wedge
- What is the mechanical advantage of a first-class lever in which the fulcrum is 10 inches from the resistance and 40 inches from the effort?
For levers, the mechanical advantage equation (memorize this) is:
Mechanical advantage = (distance from fulcrum to effort) divided by (distance from fulcrum to resistance)
Mechanical advantage = 40 divided by 10 = 4
- What does the mechanical advantage in problem #8 mean?
it means that effort is magnified by 4
- A shovel is an example of a lever. To what class does a shovel belong?
third-class lever
- A child’s see-saw is a lever. To what class does it belong?
first-class lever
- What is the mechanical advantage of a wheel and axle when the wheel has a diameter of 15 inches and the axle has a diameter of 3 inches?
Mechanical advantage = (diameter of the wheel) divided by (diameter of the axle)
Mechanical advantage = 15 divided by 3 = 5
- If a person turned the wheel of the wheel and axle in problem #12, what would the mechanical advantage do?
the applied force will be magnified 5 times
- If a person turned the axle in the wheel and axle in problem #12, what would the mechanical advantage do?
the wheel will move at 5 times the speed of the axle
- A block and tackle is composed of 6 pulleys that all work together. What is the mechanical advantage of the block and tackle system?
6
- Using the block and tackle system in problem #15, how many feet of rope would have to be pulled if a person wanted to life a load of 1 foot?
6 feet
- What is the mechanical advantage of an inclined plane with a slope of 6 feet and a height of 2 feet?
Mechanical advantage = (length of slope) divided by (height)
Mechanical advantage = 6 divided by 2 = 3
- What is the mechanical advantage of a wedge with the same dimensions as the inclined plane in problem #17?
3
- A screw with a pitch of 0.1 inches is turned with a screwdriver whose diameter is 2 inches. What is the mechanical advantage?
Calculate the circumference of the screwdriver:
Circumference = 3.1416 x (diameter)
Circumference = 3.1614 x 2 = 6.2832
Now use the mechanical advantage equation for a screw:
Mechanical advantage = (circumference) divided by (pitch)
Mechanical advantage = 6.2832 divided by 0.1 = 62.832
- If you are having a hard time turing a screw, should you get a longer screwdriver or a fatter one?
a fatter one
