Answer:
In order to encourage female workers to do her best and work harder for the company.
Explanation:
During World War II, most of men were called to go abroad and fight which left all the responsibility of industry, including the production of goods for the military, in the hands of female workforce. This is why The Westinghouse Electric and Manufacturing Company produced the "We can Do it!" poster in order to encourage female workers to do their best and work harder for the company.