Concept:When a lift descends with acceleration, the apparent weight of a person decreases.Explanation:The resultant force on the man is given by the equation T=m(g−a), where T is the apparent weight.Given: mass m=60kg, acceleration of lift a=3ms−2.Take gravitational acceleration g=10ms−2.Substitute into the formula:T=60(10−3)T=60×7=420NTherefore, the man's weight while the lift descends is 420N.Answer:D. 420N