Question

A truck traveling at 75 mi/h has a braking efficiency of 70%. The coefficient of road adhesion is 0.80. Ignoring aerodynamic resistance, determine the theoretical stopping distance on a level grade.

Answer 1

Answer:100.36 m

Step-by-step explanation:

Given

speed of truck
`u=75 mi/hr\approx 33.528\ m/s`

Braking efficiency of 70 %

i.e. braking declaration will be 70 % of frictional force

`\mu =0.8`

`a_(max)=\mu g=0.8* 10=8 m/s^2`

effective acceleration
`a_(eff)=0.7* 8=5.6\ m/s^2`

using equation of motion

`v^2-u^2=2 a s`

where v=final velocity

u=initial velocity

a=acceleration or declaration

s=displacement

here v will be zero

`-(33.528)^2=2(-5.6)(s)`

`s=(33.528^2)/(2* 5.6)`

`s=100.36 m`