UPSC Civil Service Exam Questions - Engineering

Q1:

A vehicle is moving up on an inclined plane. The vehicle has rear-wheel drive. Force of friction on the rear wheels will be in a direction

A along the plane but backward

B backward at an angle φ with the plane, where φ is the friction angle

C along the plane but forward

D forward at an angle φ with the plane, where φ is the friction angle

ANS:C - along the plane but forward

It think it should be forward.