Calculating Gravitational Force Between Earth & 2.6-kg Object

[Cloudy789]

Homework Statement

Calculate the magnitude of the gravitational force between the Earth and a 2.600-kg mass on the surface of the earth. The distance to the center of the Earth from the surface is 6370 km and the mass of the Earth is 5.98e+24 kg. HINT: This problem should take you about 5 seconds to solve. If you use G to answer this problem, you are not thinking.

M object = 2.6 kg
M Earth = 5.98 X10+24
G constant = 9.81 m/s^2
Distance between masses = 6,370,000 m

Homework Equations

F = G[(M1*M2)/r^2)]

The Attempt at a Solution

9.81[(2.6*5.98e+24)/(6,370,000^2)]
9.81[(1.5548e+25)/(4.05769e+13)]
9.81(3.832e+11)
3.7589e+12 N

Yet, Capa says this is wrong and I can't think of another way to do this. Especially not without the G Constant.

 

[Pengwuino]

This should take 5 seconds to solve as the problem stated.

F = ma

What is a? When one says F = mg, where g is the gravitational acceleration, what is the force acting upon?

 

[Cloudy789]

Wow... I am truly an idiot.
Thank you.

 

[stsraz]

Ok, so I'm working on the same problem and feel like a complete moron because I don't see what you're getting at... could someone give me a bit more information so I can understand where this problem is heading... thanks.