A block and tackle system of 5 pulleys is used to raise a load of 500N steadily through a height of 20m.The work done against friction is then 2000J.Calculate the efficiency of the system.
To calculate the efficiency of the block and tackle system, we first need to find the work input and work output of the system.
Given information:
Load lifted (Weight), W = 500 N
Height lifted, h = 20 m
Work done against friction, Wf = 2000 J
Now, let's calculate the work input and work output.
Work Input (Wi) = Force x Distance
= Weight x Height
= W x h
= 500 N x 20 m
= 10,000 J
Work Output (Wo) = Work Input - Work done against friction
= Wf = 2,000 J
The efficiency (η) of the system can be calculated using the following formula:
Efficiency (η) = Wo / Wi * 100
Substituting the values, we get:
Efficiency (η) = 2000 J / 10000 J * 100
= 0.2 * 100
= 20%
Therefore, the efficiency of the system is 20%.
To calculate the efficiency of a block and tackle system, we need to know the work input and the work output.
Here is the step-by-step explanation of how to calculate the efficiency of the system:
Step 1: Calculate the work done against friction.
Given that the work done against friction is 2000 J.
Step 2: Calculate the work input.
The work input is the product of the force applied and the distance moved. In this case, the force is the load being raised and the distance is the height through which it is raised.
Work input = force x distance
Work input = 500 N x 20 m
Work input = 10,000 J
Step 3: Calculate the work output.
The work output is the weight of the load multiplied by the height it is raised.
Work output = weight x height
Work output = 500 N x 20 m
Work output = 10,000 J
Step 4: Calculate the efficiency.
Efficiency is defined as the ratio of output work to input work. It is expressed as a percentage.
Efficiency = (Work output / Work input) x 100%
Efficiency = (10,000 J / 10,000 J) x 100%
Efficiency = 100%
Therefore, the efficiency of the block and tackle system is 100%.
work performed=500*20*9.8 N
friction=2000
efficiencey= work performed/(workpreformed+friction)