Page 80 - Physics Coursebook 2015 (A level)

Cambridge International AS Level Physics
10 Figure 4.36 shows a picture hanging symmetrically by two cords from a nail fixed to a wall. The picture is in equilibrium.
nail
50°
cord 50°
Figure 4.36 For End-of-chapter Question 10.
a Explain what is meant by equilibrium. [2]
b Draw a vector diagram to represent the three forces acting on the picture in the vertical plane.
Label each force clearly with its name and show the direction of each force with an arrow. [2]
c The tension in the cord is 45 N and the angle that each end of the cord makes with the
horizontal is 50°. Calculate:
i the vertical component of the tension in the cord [1]
ii the weight of the picture. [1]
68