An elevator has a mass of 341 kg It moves up 18 m in 22.3 s and uses 7.92times 10^4 Jof electricity. Calculate the power output of this energy transformation. (4)

1. **Calculate the work done against gravity:**<br /><br />Work (W) = force (F) x distance (d)<br /><br />The force here is the weight of the elevator, which is its mass times the acceleration due to gravity (g = 9.8 m/s²).<br /><br />F = m * g = 341 kg * 9.8 m/s² = 3341.8 N<br /><br />W = 3341.8 N * 18 m = 60152.4 J<br /><br />This is the work done *against* gravity. The elevator's motor does more work than this because it also has to overcome friction and accelerate the elevator.<br /><br />2. **Calculate the total work done by the motor:**<br /><br />The problem states the elevator uses 7.92 x 10⁴ J of electricity. We assume this energy is completely converted to mechanical work by the motor (100% efficiency, which is a simplification). Therefore, the total work done by the motor is 79200 J.<br /><br />3. **Calculate the power output:**<br /><br />Power (P) is the rate at which work is done. It's calculated as work divided by time.<br /><br />P = W / t = 79200 J / 22.3 s = 3551.57 W<br /><br />4. **Express the answer with the correct significant figures:**<br /><br />The given values have three significant figures, so the answer should also have three significant figures.<br /><br />P ≈ 3550 W or 3.55 x 10³ W<br />