Levers & more
Describe a FIRST CLASS lever (resistance, fulcrum, effort)
fulcrum is between the effort and the resistance
gears with non-parallel shafts connected to each other are called....
bevel gears
How is mechanical advantage "paid for"?
Distance
We apply less force over a greater distance using simple machines
Wheels are a modified version of what simple machine?
The center of the wheel is the fulcrum, and the resistance and effort rotate around the wheel
What is achieved by applying less force through greater distance?
mechanical Advantage
Describe a SECOND CLASS lever
(resistance, fulcrum, effort)
resistance is between the fulcrum and effort
If you wanted to change from rotational to linear motion, which gear combination would you use?
a. Bevel Gears
b. Spur Gears
c. Rack and Pinion
c. Rack and Pinion
two inclined planes placed bottom to bottom to form a point is called a ......
wedge
How do wheels impact friction?
Where should the fulcrum be placed to make lifting an object easier?
closer to the resistance
Describe a THIRD class lever
(resistance, fulcrum, effort)
effort is between the fulcrum and resistance
List 3 ways that gears are used to change motion
direction, speed, linear rotational
Which inclined plane has greater mechanical advantage?
a. 10m long and 2m high
b. 20m long and 2m high
(b)!
a = mechanical advantage of 10m/5m = 2
b = mechanical advantage of 20m/2m = 10
Why are wheels more beneficial than traditional levers?
They allow the resistance to be moved an indefinite distance because the motion can be continuous
What is the distance between threads on a screw called?
the pitch
True or False:
All levers increase mechanical advantage
False!
3rd class levers require a greater force to move the resistance, but it is applied at a shorter distance and allows the resistance to move a further distance
what is the mechanical advantage for a block and tackle system with 5 pulleys?
5
How would friction impact the force needed to slide a box up an inclined plane?
More friction = more force needed to push the box
Friction is a force that resists movement
Give 1 example of a wheel used today
Water wheel, bicycle, cars, fishing reel
what kind of simple machine is a screw?
an inclined plane
A box weighing 400 Newtons is placed on a 1st class lever 2 meters away from the fulcrum. How far from the fulcrum would you place a 200 Newton box to balance it?
4 meters from the fulcrum
To lift a box that is twice as heavy, you would need to place it twice as far from the fulcrum
a combination of fixed and moveable pulleys is called a ...
Block and tackle
Susie lifts and places a 50 Newton box on a shelf that is 3m high.
Benjamin works for iHaul, and he slides an identical 50 Newton box up a ramp that is 9m long and 3m high to get it into a moving van.
Who did more work, Susie or Benjamin?
Neither, they did the same work! Both lifted the box 3m
Challenge Question: How do fishing reels provide mechanical advantage?
The handle of the reel is longer than the width of the spool of fishing line. This allows you to apply force further from the fulcrum, which allows you to reel in a large fish more easily
What are the 2 simple machines that all other machines are based on?
inclined plane and lever