# Specific heat capacity and friction

• chanella35
In summary, the tangential frictional force of 20N exerted by band brakes on a rotating metal drum with a circumference of 0.25m is used to find the number of complete revolutions needed for the drum to increase its temperature by 5.0K. Using the equations Q=mcT and W=Fd, we can rearrange to find that d=35. Then, the number of revolutions is calculated by dividing d by the circumference, giving us 140 or 1.4*10^2 revolutions.
chanella35
1. The tangential frictional force exerted by a band brakes on a rotating metal drum of circumference 0.25m is found to be 20N. If the mass of the drum is 0.4kg and its specific heat capacity is 0.35 kJ/kg K, calculate the number of complete revolutions of the drum are required to increase its temperature by 5.0 K.

Q= mcT
W=F*d

my attempt:

Q= mc[delta]T
W=F*d

f*d=mcT
20*d=400g*0.35*5
20d= 700
d=35
revolutions = 35/.25=140 or 1.4*10^2

^^^^^is that correct?

chanella35 said:
revolutions = 35/.25=140 or 1.4*10^2
^^^^^is that correct?
No. If you have d, the number of revolutions is not d divided by the radius. It is d divided by the circumference. Also, it is a good habit to show the appropriate units every time you write down a number unless the number is dimensionless.

## 1. What is specific heat capacity?

Specific heat capacity is the amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius. It is measured in joules per gram-degree Celsius (J/g°C).

## 2. How does specific heat capacity differ from heat capacity?

Heat capacity is the amount of heat energy required to raise the temperature of an entire object by one degree Celsius. Specific heat capacity specifically refers to the amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius.

## 3. How does specific heat capacity affect the temperature change of a substance?

The higher the specific heat capacity of a substance, the more heat energy is required to raise its temperature. This means that substances with higher specific heat capacities will experience smaller temperature changes compared to substances with lower specific heat capacities when the same amount of heat energy is applied.

## 4. What is friction and how does it affect heat transfer?

Friction is the resistance force that occurs between two surfaces in contact with each other. It can cause heat energy to be converted into other forms of energy, such as sound or light, instead of being transferred as heat between the two surfaces.

## 5. How does friction affect the specific heat capacity of a substance?

Friction can cause an increase in the temperature of a substance, which can affect its specific heat capacity. This is because as the temperature increases, the particles in the substance move faster and require more heat energy to raise their temperature by one degree Celsius.

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