Question

A block and tackle system has 5 pulleys. if an effort of 1000 N is needed in the downward direction to raise a load of 4500 N, calculate :
a) the mechanical advantage
b) the velocity ratio
c) the efficiency of the system.


Ans. A) 4.5. B) 5. C). 90%

Please provide the solution

Answer 1

A block and tackle system has 5 pulleys. (n = 5)

Effort = 1000 N

Load = 4500 N

(a) The mechanical advantage M.A = load/effort = 4500/1000 = 4.5

(b) The velocity ratio = n = 5

(c) The efficiency of the system η = M.A/V.R = 4.5/5 = 0.9 or 90%

Answer 2

Answer:

The mechanical advantage, velocity ratio, and efficiency of the system are 4.5, 5, and 90%.

Explanation:

Given

Number of pulleys used=5

Effort applied(E)=1000N

Load lifted(L)=4500N

To find the mechanical advantage, the velocity ratio, and the efficiency of the system

Solution:

For a pulley system

$Velocity Ratio(V.R)= Number of pulleys used$

V.R = 5

Using the formula of Mechanical Advantage

$M.A=\frac{L}{E} \\\\=4500/1000\\\\M.A=4.5$

Then

Efficiency(η)=M.A/V.R Χ100%

=4.5×100/5

=90%

Therefore, the mechanical advantage is 4.5, the velocity ratio is 5 and the efficiency of the system is 90%.