Q1. [ Non calculator]
2. An engineer has designed a lifting device. The handle turns a screw which shortens the horizontal length and increases the vertical height.
The device is modelled by a rhombus, with each side 25 cm.
The horizontal length is cm, and the vertical height is cm as shown.
(a) Show that
. [1 mark]
(b) The horizontal length decreases at a rate of 0·3 cm per second as the handle is turned.
Find the rate of change of the vertical height when . [5 marks]