Physics; Energy

[CFC]

The following measurements are recorded during a test run.
Time taken to raise lift = 80s
Current in motor = 6.25 A
Voltage applied to motor = 240.0 V
Mass of lift = 120 kg
Height lift raised = 40m

A) Calculate the energy needed to raise the lift
B) Calculate the gain in potential energy of the lift after it has been raised
C) Account for the difference between the values in (a) and (b)

[Klaynos]

What have you tried so far on solving this problem?

[x(x-y)]

Think about the quantities they you have been given

 

- How might you compute energy from voltage, current and time?

- Gravitational potential energy is approximately = mgh, so what will Δ(mgh) be?

 

And for the last part - think about energy losses and where they might occur in such a system.

Edited December 29, 2012 by x(x-y)

[alpha2cen]

C) Potential energy is a state function, and work is a path function