Sphere sits at bottom of milk container, find mass?

AI Thread Summary
To find the mass of the glass ball sitting at the bottom of the milk container, the normal force acting on it is equal to the weight of the ball minus the buoyant force. The buoyant force can be calculated using the density of the milk and the volume of the ball, derived from its radius. The equation for the net force acting on the ball incorporates the normal force and the gravitational force. A numeric solution for the mass can be obtained by rearranging these equations. The discussion emphasizes the relationship between buoyancy, weight, and normal force in fluid mechanics.
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Homework Statement


A glass ball of radius 2.40 cm sits at the bottom of a container of milk that has a density of 1.03 g/cm3. The normal force on the ball from the container's lower surface has magnitude 7.50 *10^-2 N. What is the mass of the ball?


Homework Equations


Fb=Mf*g
d=M/V
4/3pir^3=V



The Attempt at a Solution


Fb+(7.5*10^-2)=Mball*g
but it says I am wrong
 
Physics news on Phys.org
They are probably looking for a numeric solution.

The given normal force should be equal in magnitude to 'net weight' of the glass ball in the fluid, which in turn will equal the force due to gravity on the ball less the buoyant force.
 

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