Conceptual Physics

Variables

Strategy

1. Calculate the weight of the hook, a downward force.


2. Calculate the weight of the worm, another downward force.


3. From the combined volumes of the hook and worm, compute the volume and the weight of the displaced water. Use this value for the
   upward buoyant force Fb on the bait combination.


4. With all the contributing downward and upward forces known, calculate the net force exerted by the bait on the line.

Physics principles and equations

Use the definitions of density and weight,

Archimedes’ principle states that the upward buoyant force on the bait equals the weight of the water it displaces.

Step-by-step solution

Calculate the weight of the hook.

Calculate the weight of the worm.

Calculate the weight of the displaced water, and from that the buoyancy of the bait combination.

net force of bait on line F

acceleration of gravity g = 9.80 m/s^2

buoyant force on bait combination Fb

hook worm displaced water

density ȡh = 7900 kg/m^3 ȡw = 1100 kg/m^3 ȡH2O = 1000 kg/m^3

volume Vh = 2.4×10í^8 m^3 Vw = 7.1×10í^7 m^3 VH2O

mass mh mw mH2O

weight mhgmwgmH2Og

Step Reason

1. mh = ȡhVh definition of density

2. mhg = ȡhVhg multiply by g

3. evaluate

Step Reason

4. mwg = ȡwVwg equation 2, for the worm

5. evaluate

Step Reason

6. VH2O = Vh + Vw add volumes

7. mH2Og = ȡH2O(Vh + Vw)g substitute equation 6 into equation 2

8. evaluate

9. Archimedes’ principle

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