physics
posted by jess .
A 715 kg object is lifted from the surface of the earth to a height of 880 kg above the surface of the earth.
Calculate the increase in gravitational potential energy using the exact expression and compare it with the approximate expression using g=9.81. Give the magnitude of the difference between the two expressions divided by the exact result (that is the relative error) as your answer. Use 6.0x10^24 kg, 6.4x10^6 m and 6.67x10^11 for the earth mass, earth radius and the Gravitational Constant G, respectively.

The exact PE is:
PE= GMe*m/r where r is the distance from the center of the Earth.
So compute it for both r, then subtract.
What bothers me about this question, is that you are asking for a comparision to 9.81, a three digit expression, but then using "exact" constants to two significant (three in the case of G) digits. That of course, is sheer nonsense.
Respond to this Question
Similar Questions

Physics (please check)
A 6.0kg block is released from rest 80m above the ground. When it has fallen 60m its kinetic energy is: I got 1200J as my answer mgh=(6.0*9.81* 60m)=3531.6 PE + KE= (ME + KE) 3531.6 + KE= (6.0*9.81*80m) KE= 1177.2 is that right A 6.0 … 
physics
A satellite has a mass of 100 kg and is in an orbit at 2.00*10^6 m above the surface of the Earth (a) what is the potential enegry of the satellite at this location? 
Physics 12
What is the gtravitational potential energy of a 2.00e3 kg staellite that is in an orbit that has a radius of 9.90e6 m around the earth? 
Physics
Given that the Earth's radius is 6.37x10^6 m and taking the earth's gravitational field at its surface to be 9.81N/kg, find the gravitational potential at the Earth's surface. 
space
What is the force of gravity at 220 miles above Earth's surface? 
physics
A 72.0 kg piece of a satellite left over from an explosion with zero orbital velocity in space falls from a distance of 190 above the surface of the earth down toward earth. It arrives with 29.5 Km (M="mega") kinetic energy on earth. … 
Physics
When the space shuttle (mass of the shuttle = 2 x10^6 kg) was at the outer limit of Earth's atmosphere (distance = 350 km above Earth's surface), astronauts measured the gravitational force from Earth to be equal to 1.7 x 10^7 newtons. … 
Physics
Calculate the percentage of Earth’s gravitational force on the ISS astronauts while orbiting at an altitude of 248 miles above Earth’s surface. To do this, compare the gravitational force on an orbiting astronaut to the force on … 
physics
(1a). The gravitational field strength g on the earth’s surface is 9.8N/kg. explain what this means.(b) Using the law of gravity, show that gr2= k. Where g=gravitational field strength at a distance r from the center of the earth … 
physics
(1a). The gravitational field strength g on the earth’s surface is 9.8N/kg. explain what this means.(b) Using the law of gravity, show that gr2= k. Where g=gravitational field strength at a distance r from the center of the earth …