Replace the three forces shown by an equivalent force-couple system at point A. If the forces are replaced by a single resultant force, determine the distance d below point A to its line of action. 140 N 760 mm 760 mm 130 N 760 mm 245 N Answers: Force-couple system at A. The force is positive if to the right, and the couple is positive if counterclockwise. R = i M = i N-m Single resultant force. d = i mm A-

A 1140 N crate is resting on a table connected to a 200 N block through a frictionless pulley system as shown. Friction between the crate and the table is enough to keep the system at rest. The arrows show the forces that act on the crate and the block. Determine the magnitude of each force. Friction crate Weightcrate= Normal crate= Weightblock Tensionblock Tension crate Friction crate = N crate Normalcrate= Weightcrate= unit unit unit unit unit unit Tensionerate N N N Tensionblock= Weightblock= N N

A 10 N of force is applied to a toy car and toy car accelerates to 2m/s^2. If 20 N of the force is applied on the same toy car, the toy car now accelerates to   A. 2m/s^2   B. 3m/s^2   C. 4m/s^2   D. 6m/s^2

A block with weight 50 N stops on an inclined plane which has angle 0 = 30° to the horizontal. Two observers try to analyse the forces on the block with their preferred reference. Observer A uses coordinate (xẠ, YA) as his reference while observer B uses coordinate (Xg, Yg) as her reference(See figure 1). YA Observer A Block Observer B XA W XB Figure 1. (a) Decompose the weight, W and the normal force, Ñ in the coordinate system of observer A. (b) Decompose the weight, W and the normal force, Ñ in the coordinate system of observer B. (c) Determine the magnitude of friction obtained by A and B respectively if the block tends to slide down. (d) Are the two answers in part (c) same or different? What does the result imply?