A machine with a velocity ratio of 8 requires 1000J of work to raise a load of SOON through a vertical distance of 1m. Find the etæy and mechanical advantage of machine. (0706 egeco:)
Ans.' VR = 8; input work = 1000J, Load = 500N, distance = 1m
effciency outpu-input t workwork x 1000/0
500 I x 1000/0 500/0
1000 efficiency = VR x 1000/0
= x 100
50x8
MA = = 4
IOODefine power for car engines, water pumps and air conditioners. What are its units? A water-pump can rai ROO kg of water to a height of 6m in IOS. Find the wer of the water pump. (Use g —10ms-2)
Ans: Power
The power is defined as the rate of doing work. units of power arv, watt, ergs-I and hp m = 200 kg, h = 6 m, t = IOS, g = 10ms-2
10
1200WHow many types of simple machines are there? ifa load IV is raised by a machine when an effort P is applied, what is its mechanical advantage? Has it any units?
Ans: There are three types of simple machines.
(i) the lever (ii) the inclined plane
(iii) the hydraulic press load(W) mechanical advantage (MA) = There is no units.
- How many types of simple machines are there?
(O? ev008)
Ans.' There are. three types of simple machines. ( i ) the lever (ega crowbar)
( ii ) the inclined plane (eg a screwjack)
( iii ) the hydraulic press (eg break system of car)
. A crane isdifting a 5001b piano with a velocity of 2 fts-i. Express the power ofthe crane in horse power (hp). (lhp = 550ft-lbs-l) (0? 09 •epod)
5001b, v = 2fts-l P = ?
x 2 — 1000ft-lbs-1