# Homework Help: Marble in container

1. Mar 28, 2009

### 539ay868h

Two uniform 77.4-g marbles 2.23 cm in diameter are stacked as shown in the figure in a container that is 2.70 cm wide.

a) Find the force that the container exerts on the marble at the point of contact A.
b) Find the force that the container exerts on the marble at the point of contact B.
c) Find the force that the container exerts on the marble at the point of contact C.
d) What force does each marble exert on the other?

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• ###### YF-11-55.jpg
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2. Mar 28, 2009

### Staff: Mentor

It's a statics problem, so what does that tell you? Start, as usual, by identifying all the forces acting on each marble. Hint: Use symmetry to figure out the point where the marbles touch.

3. Mar 29, 2009

### 539ay868h

I took the width of the container to minus the 2 radius of the marbles to get the horizontal length of the right-angle triangle (the blue line in the image).

2.7-2.23=0.47cm

then i took used cos(theta)=0.47/2.23
theta = 77.8

is this the correct approach?

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4. Mar 29, 2009

### orthovector

great problem

5. Mar 29, 2009

### Staff: Mentor

Excellent! Keep going.