A block and tackle system consisting of 5 pulleys is used to raise a load of 400 N through a height of 10 m. If the work done against friction is 100 j, calculate
A block and tackle consisting of 5pulleys is used to raise aload of 400N through a height of 10m, if the workdone against friction is 1000j ,calculate(i)workdone by the effort,(ii)efficiency of the system,(iii)the effort applied.
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work done = 100 Joules + m g h = 100 + 400*9.81*10
Statc
Thank you
where's the answer?
To calculate the work done, we need to consider the work done against gravity and the work done against friction separately.
1. Work done against gravity:
The work done against gravity can be calculated using the formula:
Work = Force × Distance × cos(angle)
In this case, the force is the weight of the load, which is equal to 400 N. The distance is the height the load is raised, which is 10 m. The angle between the force and the direction of motion is 0 degrees (as the force and direction of motion are in the same line). Therefore, the work done against gravity is:
Work_gravity = 400 N × 10 m × cos(0) = 4000 J
2. Work done against friction:
Given that the work done against friction is 100 J, we can directly take this value as the work done against friction.
3. Total work done:
The total work done is the sum of the work done against gravity and the work done against friction. Therefore, the total work done is:
Total work = Work_gravity + Work_friction
Total work = 4000 J + 100 J = 4100 J
Thus, the total work done to raise the load of 400 N through a height of 10 m, while overcoming friction, is 4100 J.