Answer:
a) temperature: random error
b) parallax: systematic error
c) using incorrect value: systematic error
Explanation:
Systematic errors are associated with faulty calibration or reading of the equipments used and they could be avoided refining your method.
If it is. DC, direct current reverse the polarity of power leads on the motor.
If it is a 3 phase ac alternating current, reverse any of the two of three leads.
Disconnect power before attempting.