Question

a pulley system has a velocity ratio 5.draw a neat labelled diagram of the pulley system to lift a load by applying the effort in a convenient direction. mark the tension in your diagram.
1)if the efficiency of the system is 80% finds its Mechanical advantage.
2)If a load of 10kgf is pulled up by a distance of 2 m in 10 s,calculate the power developed by the effort(given g = 10 ms-1)​

Answer 1

Mechanical advantage is 4 and the power delivered by the effort is 2000 W.

Explanation:

We are given that:

• Velocity ratio = 5
• Efficiency = 80 %

(a) Efficiency = Mechanical advantage/ Velocity ratio

80/100 = M.A / Velocity ratio

0.8 = M.A/5

Mechanical advantage = 0.8 x 5

Mechanical advantage = 4

(b) P = w d / t

P = f x s / t

P = 10000 x 2 / 10

P  =2000 W

Thus mechanical advantage is 4 and the power delivered by the effort is 2000 W

Answer 2

Given:

Velocity ratio

= 5

Efficiency

= 80%

g

= 10 ms⁻¹

To Find:

M.A (Mechanical advantage) = ?

Developed Power = ?

Solution:

(1)...

As we know,

⇒  $Efficiency = \frac{Mechanical \ advantage}{Velocity \ ratio}$

On putting the estimated values, we get

⇒  $\frac{80}{100} =\frac{M.A}{5}$

On applying cross-multiplication, we get

⇒  $0.8 = \frac{M.A}{5}$

⇒  $M.A = 0.8\times 5$

⇒  $M.A = 4$

(2)...

Now,

Power, $P=\frac{wd}{t}$

⇒             $=\frac{f\times s}{t}$

⇒             $=\frac{10000\times 2}{10}$

⇒             $=\frac{20000}{10}$

⇒             $=2000 \ Watt$

So that M.E (mechanical advantage) will be "4" and the Power will be "2000 W".