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SP6. A 60-kg man is in an elevator that is accelerating downward at the rate of

ID: 1865408 • Letter: S

Question

SP6. A 60-kg man is in an elevator that is accelerating downward at the rate of 1.4 m/s. a. What is the true weight of the man in newtons? b. What is the net force acting on the man required to pro- duce the acceleration? c. What is the force exerted on the man's feet by the floor of the elevator? What is the apparent weight of the man in newtons? (This is the weight that would be read on the scale dial if the man were standing on a bathroom scale in the accel- erating elevator.) e. How would your answers to parts b through d change if the elevator were accelerating upward with an accelera- tion of 1.4 m/s2?

Explanation / Answer

a) w = mg

w = 60*9.8 = 588 N

b)from newtons second law

f = ma

f = 60*1.4 = 84 N

c) f = w-N

N = w-f

N = 588-84 = 504 N

d) apparent weight = N = 504 N

e) f = ma = 84 N

N = w+ma = 588+84 = 672 N upwards

apparent weight = 672 N