Kinetic energy to thermal energy

[goonking]

Homework Statement

Homework Equations

Q = c m ΔT

The Attempt at a Solution

so converting 55 mph to meters per sec gives me a velocity of 24.58 m/s

kinetic energy of car is 1/2 m v²

i set 1/2 m v² = c m ΔT
plugging in v and c and masses of both

ΔT = 134.56

is that correct?

 

[Orodruin]

There is a central piece of information missing here: How many brakes does the car have? That is, how many of the car's wheels have brakes.

 

[goonking]

There is a central piece of information missing here: How many brakes does the car have? That is, how many of the car's wheels have brakes.

so there is no way i can answer this question? or do i just assume its 4? 1 for each wheel

 

[Orodruin]

so there is no way i can answer this question? or do i just assume its 4? 1 for each wheel

Unless you are a mind reader, no. I am not very familiar with cars, but I would assume that either all wheels or one pair of wheels would have brakes.

 

[Raghav Gupta]

Unless you are a mind reader, no. I am not very familiar with cars, but I would assume that either all wheels or one pair of wheels would have brakes.

So if we choose 4 wheels as it is most common, then has moment of inertia a role here?

 

[haruspex]

So if we choose 4 wheels as it is most common, then has moment of inertia a role here?

In principle, yes, but we have no information on the moments of inertia of the wheels or their radius. Besides, it would be small compared with the linear KE of the vehicle.