# How Does Braking Affect the Temperature of Car Brakes?

• Cortar
In summary, the brakes of a car with a mass of 758 kg and a velocity of 25 m/s contain 16 kg of iron, which absorbs the energy from the car as it comes to a stop. Using the formula Q=mc(t1-t2) and assuming a specific heat of 450 J/kg ¢C for iron, the change in temperature of the brakes can be calculated by finding Q, which is equal to the initial kinetic energy of the car.
Cortar
A 758 kg car moving at 25 m/s brakes to a
stop. The brakes contain about 16 kg of iron
that absorb the energy.
What is increase in temperature of the
brakes? Assume the specific heat of iron is
450 J=kg ¢
± C. Answer in units of ±C.Q=mc(t1-t2)

Ok I have the mass of the brakes and the specific heat and I know you only have to solve for the change in temperature, so I all need is Q.
I know Q is measured in Joules and J=Newton x distance, but all I am given is the velocity of the car, nothing about time, distance, or Acceleration. So how do you figure the Q?

Cortar said:
A 758 kg car moving at 25 m/s brakes to a
stop. The brakes contain about 16 kg of iron
that absorb the energy.
What is increase in temperature of the
brakes? Assume the specific heat of iron is
450 J=kg ¢
± C. Answer in units of ±C.

Q=mc(t1-t2)

Ok I have the mass of the brakes and the specific heat and I know you only have to solve for the change in temperature, so I all need is Q.
I know Q is measured in Joules and J=Newton x distance, but all I am given is the velocity of the car, nothing about time, distance, or Acceleration. So how do you figure the Q?

It comes to a stop so all the initial kinetic energy (1/2 mv^2) goes into heat. That's your Q

To calculate the energy absorbed by the brakes (Q), we can use the formula for kinetic energy: KE = 1/2mv^2. In this case, the initial kinetic energy of the car is converted into thermal energy in the brakes. So, the energy absorbed by the brakes can be calculated as:

Q = KE = 1/2mv^2 = 1/2(758 kg)(25 m/s)^2 = 237,250 J

Now, we can use the formula Q = mcΔT to calculate the change in temperature (ΔT) of the brakes. Rearranging the formula, we get:

ΔT = Q/mc = (237,250 J)/(16 kg)(450 J/kg °C) = 33.15 °C

Therefore, the increase in temperature of the brakes is approximately 33.15 °C.

## 1. What is the definition of temperature?

Temperature is a measure of the average kinetic energy of the particles in a substance. It is commonly measured in degrees Celsius (°C) or Fahrenheit (°F).

## 2. What are the three different scales for measuring temperature?

The three scales for measuring temperature are Celsius, Fahrenheit, and Kelvin. Celsius and Fahrenheit are commonly used for everyday temperature measurements, while Kelvin is used in scientific and industrial applications.

## 3. How is temperature typically measured?

Temperature is typically measured using a thermometer, which contains a liquid (such as mercury or alcohol) that expands or contracts in response to changes in temperature.

## 4. What is the freezing point and boiling point of water in Celsius and Fahrenheit?

In Celsius, the freezing point of water is 0°C and the boiling point is 100°C. In Fahrenheit, the freezing point is 32°F and the boiling point is 212°F. These temperature points are used as reference points for the Celsius and Fahrenheit scales.

## 5. How does temperature affect the states of matter?

Temperature plays a critical role in determining the state of matter of a substance. As temperature increases, substances can change from a solid to a liquid to a gas. This is known as the phase transition. The temperature at which a substance changes states is dependent on its melting point, boiling point, and freezing point.

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