The efficiency of a machine is 60%. Find in joules the workdone by a student using this machine to raise a load of 150kg through a vertical distance of 2.5m. ( g= 10m/s^2)
To find the work done by the student, we need to use the formula:
Work = force x distance
The force required to raise the load can be calculated using the formula:
Force = mass x acceleration due to gravity
Force = 150kg x 10m/s^2 = 1500N
Since the efficiency of the machine is given as 60%, only 60% of the input energy is converted into useful work. Therefore, the work done by the student can be calculated as:
Work = (efficiency/100) x input energy
Work = (60/100) x input energy
Since the efficiency is given in percentage, we divide by 100 to convert it into decimal form.
Substituting the values and solving for input energy:
Work = (0.6) x input energy
1500N x 2.5m = (0.6) x input energy
3750 = 0.6 x input energy
input energy = 3750 / 0.6
input energy = 6250 Joules
Therefore, the work done by the student using the machine is 6250 Joules.