[Science 1] Work

Question 1

What is work?

Answer 1

Using force to move an object/Transfer of energy

Question 2

What is work proportional to?

Answer 2

Force and distance

Question 3

If there is no ____, there is no work. Fill in the blank.

Answer 3

Force and movement

Question 4

What is the difference between the forces from the two formulas, only vertical and only horizontal?

Answer 4

-Vertical: Force is gravity
-Horizontal: Force is the force applied in direction of the movement

Question 5

What is negative work?

Answer 5

Force acting on opposite direction to movement (ex. air resistance, friction)

Question 6

How to calculate Sin0

Answer 6

Opposite/Hypotenuse (SOH)

Question 7

How to calculate Cos0

Answer 7

Adjacent/Hypotenuse (CAH)

Question 8

What does the equation, Fx = F d x Cos(0) describe?

Answer 8

Components of an applied force acting in the direction of the motion

Question 9

What does the equation, Fii (parallel) =mgSin(0) describe?

Answer 9

The parallel component of the gravitational force acting on an object on an incline.

Question 10

Does lifting a heavy object with a small force equal less work?

Answer 10

No

Question 11

What is power? How do you determine power?

Answer 11

-Work done in a certain time
-Depends on how fast you lift an object

Question 12

Is power proportional or inversely proportional to time?

Answer 12

Inversely proportional

Question 13

Is power proportional or inversely proportional to work?

Answer 13

Proportional

Question 14

What is mechanical advantage?

Answer 14

Measures how much a machine helps you do work

Question 15

Why does “The amount of work done at angle < the amount of work done horizontally” occur?

Answer 15

As 0 (theta) increases towards 90 degrees, it reduces friction

Question 16

How is a moveable pulley different from a fixed pulley? What is its advantage?

Answer 16

Change direction and magnitude —> Gives us mechanical advantage

Question 17

What is potential energy?

Answer 17

Energy stored in an object

Question 18

What is gravitational potential energy?

Answer 18

Stored energy an object has due to its height above the ground (more higher—> more heavier—>more gravitational energy)

Question 19

What is potential energy is proportional to?

Answer 19

Mass and height

Question 20

What is kinetic energy is proportional to?

Answer 20

Mass and velocity squared

Question 21

What is kinetic energy?

Answer 21

The energy an object has because of its motion—>faster—>more energy

Question 22

Why is kinetic energy important?

Answer 22

Calculate braking distance (more energy —> more time taken to stop)

Question 23

What is mechanical energy?

Answer 23

Kinetic + Potential

Question 24

What are the examples of kinetic energy (movement)?

Answer 24

Thermal, Mechanical, Electromagnetic, Kinetic energies

Question 25

What are the examples of potential energy (stored)?

Answer 25

Chemical, Elastic, Nuclear, Gravitational

Question 26

What is an energy that is neither in the group of potential nor kinetic energies?

Answer 26

Sonic

Question 27

What is the difference between light and radiant energies?

Answer 27

-Light: Specific type of radiant energy: often used in biological or vision -Radiant: Include all types of electromagnetic radiation, both visible and invisible

Question 28

What is Thermodynamics?

Answer 28

Study of energy

Question 29

How does the Principle of Conservation differ from the Principle of Work and the Law of Thermodynamics?

Answer 29

-Principle of Conservation: Generalized idea that the total energy is constant and energy can only be changed from one to another, not created nor destroyed — the others are more detailed explanations for this idea: -Principle of Work: No matter what tool you use (ex. pulley), the amount of work you do is the same -The First Law of Thermodynamics: In a closed system (masses are not allowed to escape and are trapped inside like a container), energy can neither be created nor destroyed, only converted from one form to another

Question 30

What is the Second Law of Thermodynamics?

Answer 30

The entropy (measure of disorder: unavailable to do work) of any isolated system will increase. For example, if you leave a room without cleaning it for a prolonged amount of time, dust would form. You need energy to keep the room in order.

Question 31

What is the Third Law of Thermodynamics?

Answer 31

As temperature gets closer to absolute zero (-273.15°C), the movement of particles (like atoms) slows down to almost nothing. At absolute zero, everything stops moving and entropy (disorder) reaches a constant low value (but is actually quite impossible to reach)

Question 32

What does efficiency measure?

Answer 32

Not all energy can be used to do work. Some energy is "lost" as heat or becomes unusable. Efficiency measures how well something uses the energy supplied to it. No system is 100% efficient.