Remember and understand
1. Which two of the following forces act on you when you float on your back in a swimming pool?
Gravitational force
B.
Friction force
c.
Traction force
D.
Buoyancy force
2. Explain the difference between buoyancy and surface tension.
3. Which fluid produces the greater buoyancy force — air or water? How do you know?
4. Nanne the three forces acting on a water spider when it is standing on a still pond.
Apply and analyse
5.
6.
State if an object would sink, rise to the surface or not move if plunged into a fluid where:
the buoyancy force is the same as its weight
a.
b. the buoyancy force is less than its weight.
Explain in terms of gravity, buoyancy and surface tension why humans can't walk on water.
1. The two forces that act on you when you float on your back in a swimming pool are the gravitational force and the buoyancy force.
2. Buoyancy refers to the upward force exerted by a fluid (such as water or air) on an object immersed in it. It is caused by the difference in pressure exerted by the fluid at different depths. Surface tension, on the other hand, is the cohesive force experienced at the surface of a liquid that causes it to behave like a stretched elastic sheet. While buoyancy is related to the displacement of fluid by an object, surface tension is related to the cohesion of the liquid molecules at its surface.
3. Water produces the greater buoyancy force compared to air. This is because water has a higher density than air, meaning that for a given volume of water, there is more mass present. In turn, this higher mass leads to a greater buoyant force exerted on an object immersed in water.
4. The three forces acting on a water spider when it is standing on a still pond are gravitational force, buoyancy force, and surface tension force.
Apply and analyse
5. If the buoyancy force is the same as its weight, the object will neither sink nor rise to the surface but remain at the same position in the fluid. This is known as being neutrally buoyant.
6. If the buoyancy force is less than its weight, the object will sink in the fluid.
7. Humans cannot walk on water because the gravitational force acting on them is greater than the buoyancy force exerted by the water's upward pressure. Additionally, the surface tension of water is not strong enough to support the weight of a human walking on it.
please shoteen the answers
1. The two forces that act on you when you float on your back in a swimming pool are the gravitational force and the buoyancy force.
2. Buoyancy refers to the upward force exerted by a fluid on an object immersed in it, while surface tension is the cohesive force experienced at the surface of a liquid. Buoyancy is related to the displacement of fluid by an object, whereas surface tension is related to the cohesion of liquid molecules at its surface.
3. Water produces a greater buoyancy force compared to air because water has a higher density than air, leading to a greater mass and thus a greater buoyant force.
4. The three forces acting on a water spider when it is standing on a still pond are gravitational force, buoyancy force, and surface tension force.
5. If the buoyancy force is the same as its weight, the object will remain at the same position in the fluid without sinking or rising. It will be neutrally buoyant.
6. If the buoyancy force is less than its weight, the object will sink in the fluid.
7. Humans cannot walk on water because the gravitational force acting on them is greater than the buoyancy force exerted by the water. Additionally, the surface tension of water is not strong enough to support the weight of a human walking on it.
Define buoyancy using an example.
Buoyancy is the upward force exerted by a fluid on an object immersed in it. It occurs due to the difference in pressure that exists at different depths within the fluid. To understand buoyancy, let's consider an example:
Imagine a person floating in a swimming pool. As the person enters the water, the water exerts an upward force on their body. This upward force is known as the buoyant force. The buoyant force is equal to the weight of the water displaced by the person's body. If the buoyant force is greater than the person's weight, they will float on the surface of the water. However, if the person's weight is greater than the buoyant force, they will sink below the surface.
This example highlights the concept of buoyancy, where the fluid (in this case, water) exerts an upward force on an object to counteract the downward force of gravity. Buoyancy allows objects to float or sink in fluids based on their density and volume.