A motor drives a load for which the torque required is given by T=80020+?m Nm load The torque–speed.

A motor drives a load for which the torque
required is given by T=80020+ωm Nm load The torque–speed characteristic of
the motor is shown in Figure P15.12.

a. Will this system start from zero speed?
Why or why not?

b. Suppose that the system is brought up to
speed by an auxiliary driver, which is then disengaged. In principle, at what
two constant speeds can the system rotate?

c. If the system is operating at the lower
of the two speeds and power to the motor is briefly interrupted so the system
slows by a few radians per second, what will happen after power is restored?
Why?

d. Repeat (c) if the system is initially
operating at the higher speed.