If the force of gravity(weight) of a 1.2kg textbook were to be measured at various distances (d) from the Earth's center, the data would appear as follows:
1) 6.4 x 10^6
2) 9.6 x 10^6
3) 16 x 10^6
4) 22 x 10^6
B) Find the distance, d, at which the gravitational force on the book is 8.0 kg*m/s^2
The Attempt at a Solution
I'm struggling with physics here...
I'm not entirely sure what my equation should be and why. Is it
F(force) = k(constant) / d(distance)^2
if so then all I need to do is find k and I can do that correct? but how exactly do I get k.
When I graph the inverse of the square I get a relatively straight line and the table looks like this
Force data stays the same
1) 24.4 x 10^-15
2) 10.9 x 10^-15
3) 3.9 x 10^-15
4) 2.1 x 10^-15
so.. to find k do I go..
(11.8 - 1.0) / [(24.4 x 10^-15)-(2.1 x 10^-15)]
which on my calculator is 4.843049327 x 10^14 and then plug it into the equation for k and plug in8.0kg*m/s^2 for F and solve for d?
also how do I deal with the units when finding k?
or do I leave out the x 10's and just have 24.4 - 2.1? or am I doing that totally wrong?
How does the weight of the book(1.2kg) come into play here in the equation? or does it?
I'm having troubles understanding why I'm doing what I'm doing in these questions I've been given, which isn't making things easier.
Thank you for any help you can provide, I have another question as well but am not sure if I should post 2 separate posts or combine the 2 different questions in the same post?