work & energy unit 4

Question 1

Forces perpendicular to the motion

Answer 1

CAN NEVER DO WORK - they are cos90 = 0

Question 2

WorkNet

Answer 2

Change in Kinetic Energy

Question 3

Direction of the displacement is in the direction of the force…

Answer 3

Cos0=1

Question 4

Direction of the displacement is in the opposing direction of the force

Answer 4

Cos180 = -1

Question 5

Constant terminal veloctiy

Answer 5

No change in kinetic energy = remains constant

Question 6

Area under Force v. Position graph

Answer 6

equals the work done

Question 7

Law of Conservation of Energy

Answer 7

The law that states that energy cannot be created or destroyed but can be changed from one form to another

Question 8

Energy is

Answer 8

the ability to do work

Question 9

Power

Answer 9

Measures the rate at which someone or something does work

Question 10

Conservation Interaction

Answer 10

The force can restore the energy it removes as it does work BACK into the object independent of the path it takes

ex: Gravitational and Elastic Potential Energy

Question 11

Energy that isn’t conserved

Answer 11

Thermal

Question 12

Potential Energy

Answer 12

Stored energy of position by an object

Question 13

Gravitational Potential Energy(Ug)

Answer 13

Energy stored in an object as the result of its vertical position or height

Ug = mgdeltay

Question 14

Elastic Potential Energy (Us)

Answer 14

Energy stored in elastic materials as the result of their stretching or compressing

Us = 1/2kx^2

Question 15

Kinetic Energy

Answer 15

energy of motion

Question 16

Translational Kinetic Energy

Answer 16

energy of a system due to the motion of the systems center of mass and velocity

KE=1/2mv

Question 17

Mechanical Energy

Answer 17

Energy possessed by an object bc of its position or due to its motion (ability to do work). It can be either kinetic or potential

Question 18

Closed Energy System

Answer 18

A conserved, isolated system in which no energy from outside the system can get in and no energy from the inside can get out

Internal forces do not affect the conservation

Question 19

Open Energy SYstem

Answer 19

System taht exchanges energy with it surroundings through external forces/work

Question 20

A single object system can only have

Answer 20

Kinetic Energy

Question 21

“Work done against friction”

Answer 21

equal to the work done by friction and does not include any work to speed an object up

Question 22

Work/total energy of a system

Answer 22

can be found by adding up the energies of the objects within the system

Question 23

Work-energy principle (words) (ch7)

Answer 23

The net work done on an object is equal to the change in the object’s kinetic energy

Question 23

(Translational) kinetic energy equation (ch7)

Answer 23

K=½mv²

Question 23

What is the difference, other than the definition, between conservative forces such as mechanical energy and non conservative forces such as friction? (ch8)

Answer 23

The work done by a conservative force is recoverable

Question 23

Work equation (no trig) (ch7)

Answer 23

W= F(vector)d(vector)

Question 23

Work equation (trig) (ch7)

Answer 23

W=Fdcosθ

Question 23

Scalar product of any two vectors A and B (ch7)
Scalar product of any two vectors A and B (ch7)

Answer 23

ABcosθ

Question 23

Work-energy principle (equation) (ch7)

Answer 23

Wnet=∆K=½mv₁²-½mv₂²

Question 24

What is potential energy? (ch8)

Answer 24

Energy associated with conservative forces that depend on the position or configuration of objects

Question 24

What is a conservative force? (ch8)

Answer 24

(A force for which) the work done by it in moving an object from one position to another depends only on the two positions and NOT on the path taken (Path independent)