K.C.S.E Physics Q & A - MODEL 2008PP1QN18

K.C.S.E Physics Q & A - MODEL 2008PP1QN18

​(a) Define the term velocity ratio of a machine.
(b) Fig. 12 shows part of a hydraulic press. The plunger is the position where effort is applied while the Ram piston is the position where load is applied. The plunger has cross-section area, a m2 while the Ram piston has cross-section area, a m2.

When the plunger moves down a distance d the Ram piston moves up a distance D.
(i) State the property of liquid pressure on which the working of the hydraulic press works. 
(ii) Derive an impression for the velocity ratio (V.R) in terms of A and a. 
c) A machine of velocity ratio 45, overcomes a load of 4.5 x 103N when an effort of 135N is applied.
Determine:
(i) The mechanical advantage of the machine; 
(ii) Efficiency of the machine; 
(iii) The percentage of the work that goes to waste. 

answers