8.(a) Define the following terms as applied in Physics:
(b) Why is efficiency of machine less than 100%? Explain briefly.
(c) Simple machine was used to raise a load of weight 4000 N through a height of 0.8 m using an effort of 800 N. If the distance moved by effort was 4.8 m, calculate the: (i) Mechanical advantage. (ii) Velocity ratio.
9. (a)A water can has three holes punched - the first at the bottom, the second at the middle and the third hole almost at the top. If water is filled in the can, how will the water spurt through the bottom and the top holes?
(b) (i) Why is it easier to cut a piece of meat with a sharp knife than a blunt knife?
(ii) The tip of a needle of hypodermic syringe has a cross-sectional area of 1 x 10 -6 m2. If a doctor applies a force of 120 N to a syringe that is connected to the needle, what is the pressure exerted at the tip of the needle?
(c) The small piston of a hydraulic press has an area of 3.0 x 10 -4 m2 and the bigger piston has an area of 2.0 x 10-2 m2 . The two pistons are in the same level. If the force of 120 N is applied to the small piston, calculate the force required to be applied to the bigger piston to stop it moving.