10 Work, Energy, Power

Question 1

what is the principle of conservation of energy?

Answer 1

energy cannot be created or destroyed

Question 2

what is work?

Answer 2

when energy is transferred to an object when acted on by a force.
W = Fs

Question 3

what is the equation for work done at an angle?

Answer 3

W = Fs cos x
(x is the angle cause i cant type theta)

Question 4

what does the area under a force-distance graph represent?

Answer 4

the total work done

Question 5

what is the equation for work done to stretch a spring?

Answer 5

W = 0.5 F (extension)

Question 6

what is the kinetic energy of an object?

Answer 6

the energy due to its motion

Question 7

what is potential energy?

Answer 7

the energy of an object due to its position

Question 8

what is the motion of a pendulum like?

Answer 8

• the bob passes through equilibrium position at maximum speed
• slows down to reach maximum height on each side of the equilibrium position

kinetic energy = loss of potential energy

Question 9

how can power be transferred?

Answer 9

through work done or heat transfer

Question 10

what is power?

Answer 10

the rate of transfer of energy

Question 11

what are the forces like when a powered object moves at constant v at constant h?

Answer 11

resistive forces are equal and opposite to the motive force

Question 12

what happens to the forces when a powered object accelerates?

Answer 12

the output forces exceed the resistive forces

Question 13

what is the motive power?

Answer 13

energy per second wasted due to resistive force + gain in kinetic energy per s

Question 14

what is useful efficiency?

Answer 14

energy transferred for a purpose