I have a question in regards to work and kinetic energy. The is #18 in Chapter 7

Question

I have a question in regards to work and kinetic energy. The is #18 in Chapter 7 of Physics for Scientists and Engineers 6th Edition by Mosca and Tipler. The actual question reads: (a) Estimate the work done on you by gravity as you take an elevator from the ground floor to the top of the Empire State Building, a building 102 stories high. (b) Estimate the amount of work the normal force of the floor did on you. Hint: The answer is not zero. (c) Estimate the average power of the force of gravity. I would really appreciate some help on this as soon as possible.

Explanation / Answer

please rate
for part a>
w=FS(cosa)

F=mg(constant) where m is ur mass ang g is gravitational acceleration

S=hieght of empire state building

a=180degree since F is downwards and S is upwards

for part b>

apply work kinetic energy theorum

since only two forces are there gravity and normal

work done by gravity(calculated in a part)+work by normal=change in K.E. i.e=0 since u r initially and finally in rest

this gives work by normal = -ve(work by gravity)

for part c>

u need more data about the acceleration or velocity during journey as u need total time taken in journey, lets say its T

then power=work by gravity/T

PLEASE RATE

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.