Question

A battery of ε = 2.60 V and internal resistance R = 0.700 Ω is driving a motor. The motor is lifting a 2.0 N mass at constant speed v = 0.50 m/s. Assuming no energy losses, find the current i in the circuit. Enter the lower current. Enter the higher current. Find the potential difference V across the terminals of the motor for the lower current.Find the potential difference V across the terminals of the motor for the higher current.

Answer 1

let I is the current in the circuit.

Power delivered by the battery = Power dissipated at resistor + power condumced by the motor

Vo*I = I^2*R + F*v

2.6*I = I^2*0.7 + 2*0.5

==> I = 0.436 A (smaller current) <<<<<<------Answer

I = 3.28 A (higher current) <<<<<<------Answer

when lower current flows,

V_temrinal = Vo - I*R

= 2.6 - 0.436*0.7

= 2.29 V <<<<<<------Answer

when higher current flows,

V_temrinal = Vo - I*R

= 2.6 - 3.28*0.7

= 0.304 V <<<<<<------Answer