# Relation between speed in water and weight

• davidthe30
In summary, the conversation discusses a lab experience where the speed of falling test tubes in water was observed. The data showed that in three out of six trials, the test tubes fell at roughly the same speed. In one trial, the heavier the weight, the slower the fall, and in two trials, the heavier the weight, the faster the fall. The goal is to find a relation between speed in water and weight. It is suggested that the weight affects the forces acting on the test tube, such as buoyancy and drag, which may explain the observed results. Equations may be useful in understanding this relation.

## Homework Statement

I was given a lab experience where I had 6 test tubes each with a different weight and I had to time the time it took to get through a 1L cylinder full of water.
Here is the problem: my data
3 times out of 6, they all took roughly the same time to fall(±0.03 sec)
1 out of 6, the heavier the weight, the slower they fell
2 times out of 6, the heavier the weight, the faster the fall
I am supposed to find a relation between the speed in water and the weight.

## Homework Equations

speed = distance/time

## The Attempt at a Solution

Since it's impossible for a heavier weight to be slower than a lighter weight, I rule out that data. I think that water offers more resistance than air to speed so my weight would be falling slower in water than in the air.

Since these are real world tests, I don't really need to calculate anything. I just need to find the relation between speed in water and weight, with the theories related to the relation. Maybe some equations, if possible. Thanks.

Weight is a force acting to bring the test tube toward the centre of the earth. There will be a buoyant force from the displaced water, and a drag force of the water acting over the surface area of the test tube. Think about how all these are related and why you might have achieved the results you did.

Based on the data provided, it appears that the relationship between speed in water and weight is not consistent. In some cases, the heavier weight falls faster and in others, it falls slower. This suggests that there may be other factors at play, such as the shape or density of the weights, that could affect their speed in water.

One possible theory to explain this variation is the concept of buoyancy. Heavier objects may have a higher density and therefore displace more water, creating a greater buoyant force that could slow down their descent. On the other hand, if the heavier weights have a more streamlined shape, they may experience less resistance and fall faster.

Another factor to consider is the viscosity of the water. Viscosity is a measure of a fluid's resistance to flow, and it can vary depending on factors such as temperature and impurities. If the water used in the experiment had a higher viscosity, it could have affected the speed of the falling weights.

To further explore the relationship between speed in water and weight, additional experiments could be conducted with different shapes and densities of weights, as well as varying levels of water viscosity. This could help to identify the specific factors that influence the speed of objects in water and lead to a more accurate understanding of the relationship between speed and weight in this context.

## What is the relation between speed in water and weight?

The relation between speed in water and weight is known as buoyancy. When an object is placed in water, it displaces a certain amount of water based on its weight. The upward force of the water, known as buoyant force, is equal to the weight of the water it displaces. This buoyant force helps to support the weight of the object, making it easier to move through the water.

## How does weight affect speed in water?

The weight of an object has a direct impact on its speed in water. Heavier objects will require more force to move through the water, making them slower. On the other hand, lighter objects will require less force and can move through the water faster.

## Does the shape of an object affect its speed in water?

Yes, the shape of an object can affect its speed in water. Objects with a streamlined shape, such as a fish or a boat, are designed to reduce drag and move through the water more efficiently. This allows them to achieve higher speeds compared to objects with a less aerodynamic shape.

## What is the importance of understanding the relation between speed in water and weight?

Understanding the relation between speed in water and weight is important for various reasons. It helps in designing efficient watercrafts, predicting the movement of objects in water, and ensuring the safety of swimmers and divers. It is also crucial in industries such as shipping and marine engineering.

## How can the speed in water and weight of an object be measured?

The speed in water and weight of an object can be measured using various techniques. For speed, methods such as Doppler sonar or timing an object over a known distance can be used. Weight can be measured using a scale or by calculating the volume of the object and the density of the water it is submerged in. Other factors such as the shape and buoyancy of the object should also be taken into consideration.