In an external focusing tachometer, the fixed interval between static hairs is 5 mm, the focal length of the objective is 25 cm, and the distance of the vertical axis of the instrument from the optical centre of the objective is 15 cm. Which one of the following is the set of constant of the tachometer ?

Which of the following data would be required for the design of progressive type computerised traffic signal system in a series of intersection on a busy street ? 1. Volume of fast moving traffic 2. Volume of pedestrain traffic 3. Volume of slow traffic 4. Approach speed of fast moving traffic. Select the correct answer using the codes given below :

A sailor, standing on the deck of a ship, just sees the light beam from a lighthouse on the shore. If the height of the sailor's eye and of the light beam at the lighthouse, above the sea level, are 9 m and 25 m respectively, what is the distance between the sailor and the lighthouse ?

The displacement of a particle undergoing rectilinear motion along the x-axis is given by x = 2t^{3}- 21t^{2} + 60t + 6 (m) The acceleration of the particle when its velocity is zero, is