En una barra de 6m que se utiliza como palanca se coloca el fulcro a 2 m de distancia del extremo derecho, como se muestra en la figura. En ese mismo extremo se requiere soportar una carga de 90N. Despreciando el peso de la palanca, determinada Fp, VMI, VMR y la eficiencia del sistema.

Fp = 45 N

VMR = 2

VMI = 2

Efficiency = 100%

Explanation:

English Translation

In a 6m bar that is used as a lever, the fulcrum is placed 2m away from the right end, as shown in the figure. At that same end it is required to support a load of 90N. Neglecting lever weight, determined Fp, VMI, VMR and system efficiency

Solution

With the diagram not massively needed to solve this question.

Although, the load of 90 N is placed at the right end of the bar, the fulcrum is placed 2 m from that right end and the balancing force or effort is placed at the extreme most left end of the 6 m bar.

Taking moment about the fulcrum,

The sum of clockwise moments must balance the sum of anti-clockwise moments.

(Load) × (Distance of load from the fulcrum) = (Balancing force) × (Distance of balancing force from fulcrum)

Load = L = 90 N

Distance of load from the fulcrum = 2 m

Balancing force or Effort = Fp = ?

Distance of balancing force from fulcrum = 6 - 2 = 4 m

90 × 2 = Fp × 4

Fp = (180/4) = 45 N

The mechanical advantages are them given as

VMR = (Load)/(Effort) = (90/45) = 2

VMI = (Distance of Effort from the fulcrum)/(Distance of Load from fulcrum) = (4/2) = 2

Efficiency is then given as the VMR divided by VMI in percentage terms

Efficiency = 100% × (VMR/VMI)

Efficiency = 100% × (2/2) = 100%

Hope this Helps!!!

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