Northern Construction and Engineering plans on opening an office in Duluth. Over the next 25 years, the office is expected to have a positive cash flow of $250,000 per year. In year 25; the office can be sold for $1M. At an interest rate of 12%, what is the equivalent present worth?

Ahelical coil spring has a mean diameter of 50 mm, a wire diameter of 5.5 mm and is wound with a pitch of 10 mm. the spring steel has an ultimate strength of 1250 mpa. find the force needed to compress the spring solid and the wire stress in this condition. state whether the spring will return to its initial length.