Lever Systems
What is the pivot point of a lever called?
Fulcrum
What is the object being lifted called?
Load
When gears touch, how do they rotate?
Opposite directions
What is another name for an inclined plane?
Ramp
This is the force you apply to lift an object.
Effort
Effort arm = 300 cm, Load arm = 1 m
→ What is MA?
A: 3 (convert 300 cm = 3 m → 3 ÷ 1)
Load = 900 N, MA = 3
→ Input force?
300 N
Driving = 15 teeth, Driven = 45 teeth
→ Gear ratio?
3 (45 ÷ 15)
Length = 8 m, Height = 2 m
→ MA?
4
this is the object being lifted.
Load
MA = 4, Input Force = 100 N
→ Output Force?
400 N
What is the trade-off when using more pulleys?
Less force, but more distance pulled
Input force = 200 N, Gear ratio = 2
→ Output force?
400 N
MA = 5, Height = 1 m
→ Length?
5 m
this is found by dividing effort arm by load arm.
Mechanical Advantage
Why does increasing the effort arm make lifting easier?
It increases MA, so less input force is needed
If force is reduced by 4×, how many supporting ropes are there?
4 ropes
Big gear → small gear
→ Speed or torque increases?
Speed increases, torque decreases
A box needs 1000 N. Ramp MA = 4
→ Force needed?
250 N
this tells you how far the rope moves when pulling.
Distance Pulled
A lever has a shorter effort arm than load arm.
→ Is MA >1 or <1? Explain.
<1, because effort arm is smaller so it doesn’t multiply force
When is Ms.A's last day?
This friday :((((
A machine needs to move quickly but with less force.
Should the driven gear be larger or smaller? Explain.
Smaller → increases speed
Why does a longer ramp reduce force?
Because it increases MA (length ÷ height)
In your gears chart, this is the force before the machine changes it.
Input Force