A block and tackle system of 5 pulleys is used to raise a load of 50kg through a height of 20m the work done against friction is 200J.Calculate the work done by effort,the efficiency of the system and the effort applied.
work done against gravity = 50*9.81 *20
total work done, add 200 J to above
efficiency = 100 * work against gravity/total work
I do not know tension in line because I do not know how your five blocks are arranged.
You didn’t put for effort formula
To calculate the work done by the effort, we can use the formula:
Work = Force x Distance
In this case, the force is the effort applied and the distance is the height the load is raised. The work done by the effort is given as 200J. We can use this information to calculate the effort applied.
First, let's find the total force required to raise the load. Since we have a block and tackle system of 5 pulleys, the mechanical advantage of the system is given by the number of supporting ropes, which is 5. The mechanical advantage (MA) is the ratio of the load force to the effort force.
MA = Load Force / Effort Force
Since the load force (weight) is given as 50kg, we can calculate the effort force as follows:
Effort Force = Load Force / MA
Effort Force = 50kg / 5
Effort Force = 10kg
Now, let's calculate the height the load is raised:
Height = 20m
Finally, we can rearrange the formula for work to find the effort applied:
Work = Effort Force x Distance
200J = Effort Force x 20m
Effort Force = 200J / 20m
Effort Force = 10N
So, the work done by the effort is 200J, and the effort applied is 10N.
To calculate the efficiency of the system, we can use the formula:
Efficiency = (Useful Work Output / Total Work Input) x 100%
The useful work output is the work done against friction, which is given as 200J. The total work input is the work done by the effort, which we calculated as 200J.
Efficiency = (200J / 200J) x 100%
Efficiency = 1 x 100%
Efficiency = 100%
Therefore, the efficiency of the block and tackle system is 100%.
To summarize:
- The work done by the effort is 200J.
- The efficiency of the system is 100%.
- The effort applied is 10N.