P7.1 Work

Question 1

Power

Answer 1

Rate at which energy is transferred

Power(W-watts) = Work(J-joules) / Change in time(s-seconds)

Power(W-watts) = Resistance(Ω-ohms) x Current² (A-amps)

Power(W-watts) = Voltage(V-volts) x Current(A-amps)

Question 2

Work

Answer 2

Using forces to transfer energy between stores
Using a force to move an object a distance
Lifting suitcases is doing work against gravity
Pulling a suitcase in a straight line is doing work against friction.
Work (joules) = Force (N) x Displacement (m)

Work = Kinetic energy

Question 3

How many joules are in a kilojoule

Answer 3

1000J

Question 4

Define power

Answer 4

Rate at which energy is transfered

Question 5

How does lubrication increase efficiency

Answer 5

Reduces friction between objects