Amotor having a maximum power rating of 8.1 x 104 watts is used to operate an elevator with a weight of 1.8 x 104 newtons. what is the maximum weight this motor can lift at an average speed of 3.0 meters per second?

If the power rating of the motor is 8x10^4 Watts and our equation for Power is:

Note that:

where g is the average gravity on Earth which is approximately 9.8 m/s^2.

And so:

In terms of force:

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s