A block and tackle system has velocity ratio 3 . Draw a labelled diagram of system indicating the point of application and direction of load and effort. A man can exert a pull of 200 kgf. a) what is maximum load he can raise with this pulley system if its efficiency is 60%? b) if effort end moves a distance 60 cm,what distance does the load move?

Asked by jatinder324 | 15th May, 2020, 10:27: PM

Expert Answer:

The labelled diagram of the block and tackle with a velocity ratio 3 is as shown, the total number of pulley is 3. 

  

 
a) 
V R space equals space 3 space

V R thin space equals space n space equals space 3
E f f i c i e n c y space o f space t h e space s y s t e m comma eta space equals space 60 percent sign space space

T h u s comma space
M e c h a n i c a l space a d v a n t a g e space equals space V R space cross times eta equals 60 over 100 cross times 3 space equals space 1.8 space
M a n space c a n space l i f t space l o a d space w i t h space e f f o r t space equals space 200 space k g f space
T h u s comma space
L o a d space equals space M A thin space cross times space e f f o r t space equals space 1.8 space cross times 200 space equals space 360 space k g f space 
 
b)  if effort end moves a distance 60 cm,what distance does the load move
 
V R space equals space fraction numerator D i s tan c e space o f space e f f o r t space open parentheses d subscript E close parentheses over denominator D i s tan c e space o f space l o a d open parentheses space d subscript L close parentheses end fraction space
T h u s comma space

D i s tan c e space o f space l o a d open parentheses space d subscript L close parentheses equals space 60 over 3 space equals space space 20 space c m space

Answered by Shiwani Sawant | 16th May, 2020, 12:38: AM