# Heating Water by Shaking: Physics Problem Solved!

• hatingphysics
In summary, a physicist must shake a thermos flask containing 380 cm3 of tap water at 58°F, falling 1.15 ft each shake, and completing 32 shakes per minute, until the water boils. Using the equation for heat transfer and assuming no thermal or mechanical losses, the physicist must calculate the mass and heat capacity of the water to find the amount of energy needed to convert the water to boiling point.
hatingphysics
A physicist, upon awaking one morning to find his stove out of order, decides to boil the water for his wife's coffee by shaking it in a thermos flask. Suppose that he uses 380 cm3 of tap water at 58°F, that the water falls 1.15 ft each shake, and that the physicist completes 32 shakes each minute. Neglecting any loss of thermal energy by the flask, how long must he shake the flask before the water boils?

Could anyone give me alittle help as to what equation to
use for this problem?

okay, assuming no thermal or mechanical losses, all of the the energy transferred from this process should be transferred into heat for the water.
Assume a constant density, find the mass, you know c , you know a specified delta T. Remember your units here. Your usual Heat capacity that you find will be in J/(g*K). for water we know this to be 4.186. Find Q. This will be how much energy will have to be converted right? You can calculate how much energy is generated/shake. The rest should be pretty easy.

I'm working on this problem too. I just was given different numbers. I have the heat required to reach the boiling point in the water as well as how much heat per shake is happening (J/shake), but I'm stuck here.

## 1. How does shaking water heat it up?

Shaking water causes kinetic energy to be transferred to the water molecules, increasing their movement and therefore their temperature.

## 2. Can any type of container be used to shake water for heating?

Yes, as long as it is a closed container to prevent water from splashing out and is strong enough to withstand the shaking motion.

## 3. What is the optimal shaking time for heating water?

The optimal shaking time depends on factors such as the amount of water, the strength of the shaking, and the starting temperature of the water. It is best to experiment and observe the temperature until it reaches the desired level.

## 4. How does the temperature of the water affect the heating process?

The higher the starting temperature of the water, the less time it will take to heat up through shaking. However, once the water reaches its boiling point, it will not heat up any further through shaking.

## 5. Are there any safety precautions to keep in mind when shaking water for heating?

Yes, it is important to use a secure and sturdy container, as well as to be cautious when handling hot water. It is also recommended to wear protective gloves to prevent any burns from hot water or the container itself.

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