A DC motor is rated at 20 A with a voltage of 115 V. When the motor is running at its maximum power, it can lift an object with a weight of 4900.00 N a distance of 10.00 m, in 30.00 s, at a constant speed.

Assuming that the difference in the power consumed by the motor and the power used lifting the object are dissipated as heat by the resistance of the motor, estimate the resistance of the motor?

1.7

V I t - FS = I²Rt

$ R = \frac{VIt - FS}{I^2t} = \frac{115\times 20 \times 30 - 4900\times 10}{20^2\times 30} = 1.7$