Answer:
1) 4000Joules
2) 25%
3) 320N
Step-by-step explanation:
A block and tackle consisting of 5 pulleys is used to raised a load of 400N through a height of 10m.If the work done against friction is 100j.
Calculate;
1)The work done by the effort
2)The efficiency of the system
3)The effort applied
1) Workdone by the effort is the work input = Load * distance moved by the Load
Workdone by the effort = 400 * 10
Workdone by the effort = 4000Joules
2) Efficiency = Work output/Work input * 100
Work output = work done against friction = 100 Joules
Efficiency = 100/4000 * 100
Efficiency = 10000/4000
Efficiency = 25%
Hence the Efficiency of the system is 25%
3) Using the efficiency formula:
efficiency = MA/VR * 100
Velocity ratio = 5
MA = Load/Effort
efficiency = (L/E)/5 * 100
25 = 400/E/5 * 100
25/100 = 400/5E
0.25 = 400/5E
0.25 * 5E = 400
1.25E = 400
E = 400/1.25
E = 320N
hence the effort applies is 320N