Question

See Attached picture.

Answer 1

We use the Work formula to solve for the unknown in the problem which is W = F x d. First, we solve for the Net Force acting on the car. The Net Force is the summation of all forces acting on the object. For this case, we assume that Friction Force is negligible thus the Net Force is equal to:

F = mgsinα in terms of SI units and in terms of english units we have F = m(g/g₀)(sin α) where g₀ is the proportionality factor, 32.174 ft lb-m / lb-f s²

F = 2500 (32.174/32.174) (sin 12°) = 519.78 lb

W = Fd = 519.78 lb (400 ft) = 207912 ft - lb or 20800 ft-lb