K.C.S.E Physics Q & A - MODEL 2005PP2QN05

K.C.S.E Physics Q & A - MODEL 2005PP2QN05

​(a) State Hooke's law 
(b) One of a piece of a rubber was fixed to a rigid support and the other end pulled with a force of varying magnitude. The graph in fig 6 shows the relationship between the force (N) and the extension (cm)

Using the graph, determine
(i) The stretching force at the elastic limit
(ii) The tensile stress in the rubber at an extension of 5 cm if the cross-section of the rubber is 0.25cm2
(iii) The tensile in the rubber at an extension of 5cm if the original length was 2 m 
(c) In Fig 7. girders AB, BC, CD, ED, EB and BD were joined to make the rigid structure shown. The load W hangs from the structure as shown.

Which of the girders can be replaced with strings without affecting the structure?

answers