Question

What is the change in gravitational potential, energy
when a 1600 lb elevator moves from street level to top of empire State building 1250 ft above street level.​

Answer 1

Explanation:

1600lb=7117N

1250ft=381m

They're asking you here for gravitational potential energy. That's equal to mgh. You've already got mg (force of gravity on the elevator) and h (height that the elevator reaches) so all you need to do is multiply the two numbers you had.

There’s only one thing here which might be potentially confusing, and that’s the significant digits. Both 7117 and 381 are only one sigfig each. Because of that, your answer can only be one sigfig. Some teachers would accept the answer you would automatically reach, others might insist that - due to sigfigs, the answer here would be 2,711,577J

Answer 2

Answer:

The change in potential energy is 2.71MJ(Mega Joule)

Explanation:

Given that,

The mass of elevator is 1600lb

The height of empire state building above sea level is 1250ft

We first convert the given quantities into SI system.

Mass is

$m = 1600 \times 0.454kg = 725.74kg$

Height is

$h = 1250ft = 1250 \times 0.305m \\ = 381m$

The Potential energy at sea level.us taken as zero.

Therefore the change in potential energy is given by relation

$∆P.E=mgh$

Substituting given values,we get

$∆P.E=725.74 \times 9.81 \times 381 \\ = 2712533.08J \\ = 2.71MJ$

Therefore,the change in potential energy is 2.71MJ(Mega Joule)

#SPJ2