試題詳解

4. A truck of mass M, including four solid cylindrical tires, requires power to accelerate at a given rate. Each tire can be approximated as a solid cylinder with mass m and radius R. Derive an expression for the power needed to accelerate the truck as a function of its mass M, the mass of each tire m, the truck's speed v, and its acceleration a. Your answer should contain M, m, v, and a.
(A) (M+2m)va
(B) (M+m)va
(C) (M+2m)(y/a)
(D) (M+m)(v/a)
(E) None of the above.