- #1
struggles
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- 0
Homework Statement
Three uniform spheres are fixed at positions shown in the figure.
i) What is the magnitude of the force on a 0.0150-kg particle placed at P?
ii) What is the direction of this force?
iii) If the spheres are in deep outer space and a 0.0150-kg particle is released from rest 300 m from the origin along a line 45∘ below the -x-axis, what will the particle's speed be when it reaches the origin?
Homework Equations
Fg = -GMm/r2
The Attempt at a Solution
I think I've got the answers for part i) F = 9.67×10-12 N
ii) 45°.
I got i) by simply working out the force due to gravity on P due to each of the spheres and then resolving them to see the component of the force along the 45° angle.
However part iii) I'm struggling with. Obviously the force will increase as P gets closer to the origin. This will mean that the acceleration will increase.
I think Fg ∝ 1/r2 and the acceleration a = Fg/m.
Because the acceleration is non constant I think I have to integrate a with respect to t to find v. However there is no mention of t anywhere in this question! From here I'm not quite sure where to go and any help would be greatly appreciated!