Week 7

Question 1

What is the equation for the sum of forces in a vehicle on a slope?Draw it and the equation

Answer 1

If drawn correctly the equation is max= Fxf +Fxr -Rxf-Rxr-Fd-mgsin(angle)

Question 2

How does the wheel rotating cause antisymmetric stress, how does this cause a resistive force on the wheels

Answer 2

The antisymmetric stress is caused by the wheel rotating, this causes a moment inverse to the direction of rotation of the wheel to resist rotation

Question 3

What is the equation for the drag force?

Answer 3

Fd = p/2 CdA*Vx^2

Question 4

What is the cause of rolling resistance?

Answer 4

Rolling resistance is due to the following factors:
Air in tires is accelerated
Slip in the contact patch
Energy is dissipated as rubber is deformed in entry and exit from the contact path.

Question 5

What is the rolling resistance equation?

Answer 5

Rx = fr*N, where fr is the rolling resistance coefficient.

Question 6

Derive the equations for Nf at stationary level, low-speed acceleration- level, and stationery with an incline

Answer 6

1-Nf =Mgc/l = Nfs
2- Nf = Nfs - Max h/l
3- Nf = Nfs- Mg (h/l) *sin(angle)