Trouble Finding Change in Temp Given KE = Q (Thermal Energy)

In summary, a 3kg projectile traveling at 100 m/s is stopped by being shot into an insulated tank containing 100kg of water. If the kinetic energy of the projectile is completely converted into thermal energy, the temperature of the water would increase by approximately 0.036 degrees Celsius. This was calculated by equating the kinetic energy to the thermal energy and using the specific heat of water to solve for the change in temperature. The heat capacity of the projectile has not been specified and could potentially be included in the calculations.
  • #1
Oannes
26
1

Homework Statement


A 3kg projectilce traveling at 100 m/s is stopped by being shot into an insulated tank containg 100kg of water. If the KE of the projectile is completely convereted into thermal energy, how much will the temp of the water increase in degrees celcius? The standard heat of water is 1 cal/g C.

Homework Equations


Thermal Energy = mass * Specific Heat * change in temperature
Kinetic Energy = 1/2 * mass * Velocity2
KE = TE

The Attempt at a Solution



So did all my conversions to get like units below.

1cal/g C = 4.18J/.001kg * C (Specific Heat of Water)

Then solved for Kinetic Energy:

KE = 1/2 (3kg) (100m/s)2
KE = 15000kg m2/s2 = 15000J

Then solved for Thermal Energy setting Kinetic equal to Thermal as it states in the problem:

15000J = 100kg (4.18J/.001kg C) * Change in Temp
15000J = 418000J/C * Change in Temp
.0359 C = Change in Temp


Now this seems to be my answer, and I think that maybe such a miniscule change could be my answer considering the circumstances, however I fear that I have done something wrong somewhere and cannot find it. Most of my problems so far have involved significant temperature change so I feel they are either changing things up or I have made a mistake somehwere. Is all my logic correct? or have I messed up somewhere? Also I understand this question could fall under physics, however they have us working this out in my Engineering and Problem Solving course. Thanks so much in advance.
 
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  • #2
Oannes said:
Is all my logic correct?
The only "correction" that might be applied is to include the heat capacity of the projectile; it hasn't been specified, and could be argued to be < 4 mK , the uncertainty of the experiment, or, included if you feel that it is necessary.
 

1. What does the equation KE = Q (Thermal Energy) mean?

The equation KE = Q (Thermal Energy) represents the relationship between kinetic energy (KE) and thermal energy (Q). It means that the kinetic energy of a system is equal to the amount of thermal energy transferred to the system.

2. How does temperature affect thermal energy?

Temperature is directly proportional to thermal energy, meaning that as the temperature of a system increases, so does its thermal energy. This is because temperature is a measure of the average kinetic energy of particles in a system, and higher temperatures mean that particles are moving faster and have more kinetic energy.

3. Can thermal energy be converted into other forms of energy?

Yes, thermal energy can be converted into other forms of energy, such as mechanical energy or electrical energy. This is the basis of many energy conversion processes, such as the conversion of heat into mechanical energy in a steam engine.

4. How is thermal energy related to the concept of heat?

Thermal energy and heat are closely related concepts. Heat is a form of energy that is transferred between two objects or systems due to a temperature difference, and thermal energy is the total kinetic energy of particles in a system. Heat can increase the thermal energy of a system, and thermal energy can be converted into heat when it is transferred to another system.

5. Can thermal energy be created or destroyed?

According to the law of conservation of energy, energy cannot be created or destroyed, only transferred or transformed. This applies to thermal energy as well. While thermal energy can be converted into other forms, it cannot be created or destroyed on its own.

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