A battery drives an electric motor which raises a 20 kg mass at a steady speed.

[apparatus82]

1. A battery drives an electric motor which raises a 20 kg mass at a steady speed of 3m/s vertically upwards. If 90% of the electrical energy supplied is converted to mechanical energy and the current flowing is 5 A, find the emf of the battery.



2. W=QV
p=mv
P=IV
K.E=.5mv^2


3.

K.E= 90 joules
90/.9=100 joules
W=QV
100=5(1.6x10^-19)V
V = 1.25 x10^20 ?


Correct answer: 130.7 V
Any help is highly appreciated.

 

[apparatus82]

1. A battery drives an electric motor which raises a 20 kg mass at a steady speed of 3m/s vertically upwards. If 90% of the electrical energy supplied is converted to mechanical energy and the current flowing is 5 A, find the emf of the battery.



2. W=QV
p=mv
P=IV
K.E=.5mv^2


3.

K.E= 90 joules
90/.9=100 joules
W=QV
100=5(1.6x10^-19)V
V = 1.25 x10^20 ?


Correct answer: 130.7 V
Any help is highly appreciated.

Scratch that. I got it now!
Work done = Force x distance
Power = Work done/ Time
Therefore, Power = Force x Speed