energy and power

Question 1

what is mechanical energy?

Answer 1

• kinetic energy (movement)
• potential energy (position)

Question 2

what are the units for energy and the base SI units?

Question 3

conduct dimentional analysis on kinetic energy and gravitational potential energy to show they are both equations of energy

Question 4

when is mechanical energy conserved?

include equation

Answer 4

if the only force acting on a body (doing work) is weight

Question 5

what are dissipative forces?

Answer 5

eg: friction and air resitance
* loss of mechanical energy in the form of heat/ sound
cannot be recovered

Question 6

what are conservative forces?

Answer 6

eg: tension/ gravity
* can be recovered
* eg: potential energy gained moving up a hill and then regiang in form of kinetic energy

Question 7

what is work done?

Answer 7

(component of force in direction of movement) × distance

work is only done when there is movement

Question 8

what is the work energy principle?

formula

Question 9

what is the work done when a force acts perpendicular to it’s line of action?

Answer 9

ZERO

no componenet parallel to line of action

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

Answer 14

Question 15

Answer 15

Question 16

what are the two formulae for power?

Answer 16

assumption that work is being done at a constant rate

Question 17

how do you convert units like horsepower in the calculator?

Answer 17

1. options
   2 . convert and use arrows

1 horse power = 33000 foot pounds per minute

Question 18

Answer 18

Question 19

Answer 19

Question 20

why may energy methods be the only way of solving a problem?

Answer 20

acceleration may not be constant and so suvat is not applicable