Mechanical Systems
Definition of mechanical system
100: An assembly of physical components (gears, motors, linkages) that work together to manage energy, force, and motion to achieve a function.
Name 4 simple machines
Inclined plane, lever, pulley, wheel and axle
Work formula?
W = F x d
This force always opposes motion
Friction
Pressure formula
P = F / A
Is a rock a mechanical system? Explain why or why not.
No — it has no parts working together to transfer force/motion.
In this class of lever, the fulcrum is in the middle.
First-class lever
A force of 20N moves an object 9m. What is the work done?
180J
Can a machine be 100% efficient in the real world? Why or why not?
No — some energy is always lost due to friction.
What is the MA of a wheel that is 4m and an axle that is 1m?
4/1
= 4
Name 2 mechanisms that make a bicycle a mechanical system.
Chain, gears, pedals, wheels, brakes, sprockets. (Any 2)
This simple machine is also called an inclined plane.
Ramp
A person pushes with 75 N over 2 m. Find the work done.
150J
Give two examples each where friction is GOOD and two where friction is BAD.
Good = walking, brakes, bike tires. Bad = blisters, heat loss in machines, worn gears.
What is the gear ratio formula
Driver teeth / follower teeth
Why is a vending machine considered a mechanical system?
It uses motors, buttons, motion transfer, and controlled movement to dispense items.
This class of lever always makes lifting easier because the load is in the middle.
Second-class lever
A machine has MA = 5. If input force is 80 N, what output force is created?
400N
Why do machines make life easier even though they don’t reduce total work?
500: They reduce effort by changing force, direction, speed, or distance.
What is Pascals Law
A pressure change applied to a confined, incompressible fluid is transmitted equally to every point of the fluid and to the walls of the container
Explain why a stapler is a machine AND part of a mechanical system.
Stapler = machine because it changes force to make work easier; part of a mechanical system because multiple parts work together.
Name 3 reasons why we don’t use ramps everywhere instead of stairs?
Space, time, efficiency
What are the units for work and mechanical advantage?
Work = Joules
MA = none
If input work = 500 J and output work = 300 J, what is the efficiency?
300/500 x100
= 60%
if Gear A has 24 teeth and is the driver gear, and Gear B has 8 teeth and is the follower gear... If gear A spins 3 times, how many times will gear B spin?
24/8 = 3
3 x 3 spins = 9 times