試題詳解

20. Consider the following experimental arrangement, see Figure 6. A block of mass m is released at rest (point A) and is dragged along a table by a constant force F₀ =5.0N, where the unit N means Newton. Assume that the surfaces of the table and the pulley are frictionless. Under the action of constant force F₀, the mass m moves from point A (a=π/6) to point B(β=π/4) and has a horizontal displacement s = 2.0 meter. Find the work W carried out by the constant force F₀ from A to

(A) W =0(N．m)
(B) W =10.0(N．m)
(C) W=8.0(N．m)
(D) W =1.6(N．m)