- #1
series111
- 54
- 0
Homework Statement
A screw jack has a single start thread of pitch 7mm and a operating handle 800mm long.when raising a load of 750kg the effort required on thev end of the handle is 26N.
determine for these operating conditions the following :
(a) the mechanical advantage
(b) the velocity ratio
(c) the efficiency of the machine
(d) the law of the machine
Homework Equations
ma = load/effort
vr = 2 x pie x r/p
effiency of the machine = ma/vr x 100%
law of the machine = E = aw+b
The Attempt at a Solution
(a) mechanical advantage = 750 x 9.81/26N = 282.98
(b) the velocity ratio = 2 x pie x 800mm/7mm = 718.07
(c) the effiency of the machine = 282.98/718.07 x 100% = 39.40%
(d) the law of the machine this is where i am struggling i no the formula is E = aw+b
where a is the velocity ratio and w is the load however what does the b stand for and if i need to caculate this how do i do this please help ...