# Physics

posted by .

A hollow plastic spherical bobber of mass 0.005 kg and volume of 50 cm3 floats on the surface of a lake supporting a submersed fishhook and a bait with a combined mass of 0.01 kg and a combined volume of 2 cm3. The density of water is 0.001 kg/cm3.

If a fish grabs the bait, find the minimum downward force, Ffish, it must exert to pull the bobber completely under the surface of the water. You may assume that the apparent weight of the fish is zero, and the fishing line is completely slack.

• Physics -

So you want the bouyant force of the submerged bob.

Mass: .005+.01 kg
Volume: 50cm^2+2cm^2

mass of displaced water: densitywater*volume=1g/cm^3*52cm^2=52g

bouyant force= 9.8N/Kg * (.052kg)

net force=9.8(52-15)N

check my thinking.

• Physics -

thank you so so so much. the answer is .3626

• Physics -

The force that is

• Physics -

The force that is exerted by the bobber and the hook and bait will be equal to the combined mass and the combined volume (0.015 kg and 52 cm^3)-- not sure why though.

The buoyant force if the object was completely submerged would be the density of water*V displaced*g (.001*52*9.8).

The difference between these two (0.3626) would be the force the fish would need to exert to completely submerge the bobber.

## Similar Questions

1. ### Physics

A hollow plastic sphere is held below the surface of a freshwater lake by a cord anchored to the bottom of the lake. The sphere has a volume of 0.600m^3 and the tension in the cord is 840N . What is the mass of the sphere?
2. ### physics

A hollow plastic sphere is held below the surface of a freshwater lake by a cord anchored to the bottom of the lake. The sphere has a volume of 0.600m^3 and the tension in the cord is 840N . What is the mass of the sphere?
3. ### physics

A plastic bobber just barely floats in water. If it weighs 2N in the air, what is its volume
4. ### physics

A plastic ball has a volume of 300 cm3 and a mass of 30 g. What fraction of the ball's volume will float above the surface of a lake of fresh water?
5. ### phy

A piece of plastic barely floats in water. If it has a mass of 20g, what is its volume?
6. ### physics

A foam plastic ( sg = 0.58 ) is to be used as a life preserver. What volume of plastic must be used if it is to keep 20 % (by volume) of a 75 kg man above water in a lake?
7. ### Physics ( Thickness of a Spherical Shell)

Aluminum floater: A spherical shell with an outer radius R=2 cm is made of aluminum (mass density of Al is 2.7 g/cm3). How thick is the shell if the average density of the spherical object is exactly 0.5 g/cm3 ?
8. ### Physics

Each cubic centimeter of silver has a mass of 10.5 g. (a) What is the mass of 62.9 cm3 of silver?
9. ### Physics

Each cubic centimeter of silver has a mass of 10.5 g. (a) What is the mass of 62.9 cm3 of silver?
10. ### Science

What is the density of a book whose mass is 1,800 g and whose volume is 300 cm3?

More Similar Questions