Chapter7️⃣ Flashcards
(39 cards)
How is work and energy represented?
In joules
What does work involve?
The exchange of energy for some change in a physical system
When does mhecanical work occur?
When a force acts on a object to move it in a direction parallel in a force vector
What is done when the force acts on a system in the same direction as the systems motion?
Positive mhecanical work
What is the object at when the force acts perpendicularly to the objects displacement?
When either the force or displacement is at zero
What does Newton’s second law of motion have to do with this?
A larger force results in a greater acceleration for a given mass
What is power?
The rate of doing work
What is the unit for power?
Watt- named after James Watt the inventor who vastly improved the efficiency of the steam engine
What are tools made of?
Simple machines
Why can’t you get more energy out of the simple machine than you put into it?
It does not create energy
What is the system to be moved called?
Load or resistance
The force needed to just begin moving the resistance is called what?
Resistance force
The force exerted on the simple machines is called what?
The effort force
What is the distance principle?
To conserve work and energy, simple machines compensate for a smaller effort force by exerting that force over a longer distance
What is a lever?
A simply rigid bar that rest on a fulcrum
What is the fulcrum?
A pivot point
What is rotational equilibrium?
When it is balanced on the fulcrum
What is moment or torque?
When a force acts perpendicularly on a lever rotating around a pivot point
What is a mechanical moment?
Simply the product of the force and distance from the pivot point where the force is applied
What is moment arm?
The fixed distance
Every lever system is divided into what?
Effort arm and resistance arm
What is first class lever?
The fulcrum is between effort and resistance arm
What is a second class lever?
It has the fulcrum at the end of the lever arm and the resistance between the fulcrum and resistance
What is a third class lever?
The fulcrum is located at the end of the lever arm and the resistance between the resistance and fulcrum
