Answer:
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!!!
