2.3 Work, energy, and power

Question 1

Define joule

Answer 1

One joule is the energy required when a force of one newton acts through a distance of one metre

Question 2

Principle of conservation of energy

Answer 2

Energy can not be created or destroyed

Question 3

Hence: J = Nm

Answer 3

Work done (in J) = force exerted (in N) x distance moved in the direction of the force (in m)

Question 4

Define the quantity power

Answer 4

The rate of doing work, the number of joules that can be converted pr second:
power (in W) = work done/time
or
= force x distanced moved by force/time
or
= force x speed

Question 5

1 W can be written as..

Answer 5

1 Js^-1

Question 6

Ek = 1/2mv^2, Ek = Fs

Answer 6

Kinetic energy = mass*velocity^2

Kinetic energy = Force*speed

Question 7

KE=1/2m(v^2-u^2)

Answer 7

Change in KE, SUVAT

Question 8

Epot = mgΔh

Answer 8

Potential energy = kggm