Calculating Gravity: Determine G from Acceleration

  • Thread starter Thread starter Miike012
  • Start date Start date
  • Tags Tags
    Gravity
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
2 replies · 2K views · last reply
Miike012
Messages
1,009
Reaction score
0
Sorry.. I think I posted this post already but I can't find the original thread..

Problem:
Two spheres of masses m = 1.00 g and m' = 1.00 * 10^2
kg are isolated from all other bodies and are initially at
rest, with their centers a distance r = 15.0 cm apart. One
minute later, the smaller sphere has moved 0.534 mm
toward the larger sphere. Compute the acceleration and
the value of G.

Solution:
Acceleration: x = xi + Vxi(t) + (a)(t^2)/2

0.149m = a(1s)^2/2
a = (0.149m)(2) = 0.3 m/s/s

Is this correct for acceleration?

Could I have also used Newtons second law some how to solve for acceleration?
such as...
F = (m1)(m2)(G)/.149^2 = 2.98*10^-11
F = F1... 2.98*10^-11 = (m1)(a)
a = 2.98*10^-11/m1 = 2.9*10^-7

But obviously these answers are not the same...
 
Attachments
  • Two-panel schematic of two blocks on a horizontal line, labelled m1 (small) and m2 (large). Top: at rest, separated by 0.15 m, with forces F1 pointing right on m1 and F2 pointing left on m2. Bottom: final position at t = 1 sec, with m1 shifted right, separation 0.15 m - 0.534*10^-3 m, and forces F1' and F2'.
    Diagram.png
    9.3 KB · Views: 451
Last edited:
Physics news on Phys.org
Miike012 said:
?
Read the rules for posting on this site. "Bumping" is not allowed until 24 hours have elapsed.