Question

When you skid to a stop on your bike, you can significantly heat the small patch of tire that rubs against the road surface. Suppose a person skids to a stop by hitting the brake on his back tire, which supports half the 80 kgkg combined mass of the bike and rider, leaving a skid mark that is 40 cmcm long. Assume a coefficient of kinetic friction of 0.80.

How much thermal energy is deposited in the tire and the road surface?
Express your answer with the appropriate units.

Answer 1

E = 251.14 J

Step-by-step explanation:

The thermal energy deposited in tire can be given by the following formula:

`E = fd`

where,

E = thermal energy = ?

f = frictional force = μW = μmg

d = distance covered = 40 cm = 0.4 m

m = mass = 80 kg

μ = coefficient of friction = 0.8

Therefore,

`E = \mu mgd\\E = (0.8)(80\ kg)(9.81\ m/s^2)(0.4\ m)`

E = 251.14 J